Changelog

Diagramon 3.13.1 is a small release: Mermaid moves to the top of the format list; the rest is internal cleanup.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• Mermaid is first when creating a document: in the Ctrl+N / tab + / File → New chooser, the first card is Mermaid. The order applies to four places at once — the New dialog, the tab strip's "Convert" menu, and both the direction list and the matrix of "Conversion capabilities" — because they all read the same format registry, so there is no "changed here, not there".
• New order: Mermaid → drawio → Excalidraw → DOT → D2 (drawio used to be first).

Fixes

• Internal: fixed an intermittently failing acceptance probe (the canvas "event ownership" assertions waited on a 120 ms poll and could be fooled by timer throttling on a busy machine). Invisible to users, but our gate no longer goes red at random.
• Internal: the browser prototype's format list now matches the same order (it has no Rust backend and has to keep a copy; the two lists differing is exactly what the new assertion caught).

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.13.1_x64-setup.exe and run it. Users on an older version get this release through Help → Check for updates (the update package is this installer; the signature is in latest.json).

The installer is not yet Authenticode-signed, so Windows SmartScreen may show a prompt.

Diagramon 3.13.0 is a maintenance release focused on security and data integrity — few new features, but a batch of fixes for problems that could silently corrupt your documents or take the process down.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• Safer to open a diagram you did not write: links rendered out of a diagram are filtered against a protocol allow-list (javascript: is stripped, including the tab/newline-mangled variants), and the animation-driven rewrite trick is removed outright. The content security policy now also covers the drawio / Excalidraw canvases themselves, not just the shell window.
• Auto-palette no longer corrupts D2 documents: styles for nodes inside a container are written as container.node (they used to land at the top level, which created a whole duplicate set of nodes); names with spaces, # or ; are quoted; and markdown inside |md … | blocks is no longer mistaken for nodes and written back into your source.
• Switching tabs no longer mixes diagrams: canvas events now carry which document they belong to, so a late autosave from the previous document is dropped instead of landing in the newly opened one.
• Deeply nested .dot files no longer take the process down: beyond 256 levels you get a clear "line N: subgraph nesting exceeds 256 levels" instead of a stack overflow, and an unclosed subgraph no longer makes "Format" produce hundreds of megabytes.
• CRLF files stop being "dirty forever after one edit": edit a Windows-newline file and undo it, and the dirty flag clears correctly; saving no longer silently rewrites the whole file to LF.
• Better behaved toward AI upstreams: Ollama tool-call arguments are parsed correctly (they used to be treated as empty, which made the tool loop useless there while still costing you tokens), and an oversized upstream response now fails with a clear error instead of eating all the memory.
• Upgrading no longer drops unsaved work: the installer terminates the app, and unsaved documents used to live only in the draft store behind the "auto-save" toggle (off by default). Dirty documents are now always drafted first, so they can be recovered.

Fixes

• Search crashed (the panic took the whole process down) on text containing İ / ẞ.
• A } inside a trailing comment pushed the palette block outside the graph, making the DOT invalid.
• The first node of an unnamed digraph { … } could never be coloured.
• DOT → D2 silently dropped isolated nodes (legends, single state nodes).
• Converting the same Mermaid source to D2 twice produced different bytes, leaving the document permanently dirty and filling diffs with noise.
• An invalid stroke-width was copied verbatim into DOT (potentially injecting arbitrary attributes).
• Rounded nodes lost their rounding through "colour, then convert to DOT".
• Renaming a file in the workspace and pressing Ctrl+S resurrected the old file name on disk.
• Cloud documents lost their version number after switching tabs, causing duplicate documents in the cloud.
• "Show in file manager" never worked (it called an API that does not exist); it now really reveals the file.
• Changing a provider's base URL kept reusing the old key — it now asks for the key again, so a key can no longer be sent to an address that was changed underneath it.
• The remote-debugging port was honoured in release builds too — it is now development-only.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.13.0_x64-setup.exe and run it. Users on an older version get this release through Help → Check for updates (the update package is this installer; the signature is in latest.json).

The installer is not yet Authenticode-signed, so Windows SmartScreen may show a prompt.

Diagramon 3.12.6 reorganises the About window into two parts: a header that says what this is and where to find it, and a single list underneath.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• A two-line header: the first line is the product name, the second is "version · platform" plus the official site and source code. The two links sit vertically centred with the version text, and drop to their own line (left-aligned with the version) when the window is too narrow.
• No text labels on the links: www.diagramon.com and github.com/westsource/diagramon already say where they go; hovering still shows "Official site: https://…" and screen readers read the same name. The system browser opens only when you click.
• One list: the format table loses its "Formats" heading and header row — six rows read directly. The editor (CodeMirror 6) is the last row, side by side with the formats: same chip in the name column, - in the extension column, "Editor" in the note column.
• Three duplicates removed: the heading and header row, the repeated format/rendering rows above the list, and the author/licence line at the bottom.

Fixes

• Formats were listed twice in About: a one-line summary at the top and a full table below — the same information twice, with rendering technology mixed into the format table as if it answered two questions. They are now a single list, and the editor sits in the row where it belongs.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.12.6_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.12.5 brings Mermaid 12's swimlane diagrams into editing, preview, outline, AI and conversion.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• Swimlanes actually render now. Start the source with swimlane-beta LR (or TB); every top-level subgraph is a lane, and nodes and edges keep exactly the flowchart syntax. The preview used to flatten them into an ordinary flowchart — nodes were there, the lane frames and lane titles were not.
• No dead "Layout" button. A swimlane diagram's layout is fixed to swimlane, so the preview top bar keeps only Look / Colours and the subtitle says so; the status bar, command palette and layout pop-up no longer offer it either.
• Outline speaks the diagram's language: the top-level groups of a swimlane document are called "lanes" rather than "subgraphs".
• Conversion: swimlane diagrams convert to DOT (lane → cluster) and D2 (lane → container), and Excalidraw still goes through its engine; drawio is explicitly unsupported — the Mermaid importer bundled with drawio does not recognise swimlane-beta, so the dialog marks that target unavailable and says why instead of letting you wait for an engine failure.
• The AI can write swimlanes: ask for "a swimlane diagram split by team" and the model gets the swimlane-beta syntax and semantics; a returned swimlane source is now recognised as code (it used to be discarded as prose).
• Fixed along the way: Mermaid with front matter. --- config: … --- and multi-line %%{init: …}%% are no longer mistaken for the diagram header / a statement — such files now convert to DOT and D2; a flowchart header without a direction is treated as TB (Mermaid accepts it; the old code said "missing direction").

Fixes

• Swimlanes degraded to a plain flowchart: the preview passed the global layout (ELK by default) to Mermaid, overriding the diagram's own swimlane layout. Swimlane documents now skip the global layout and pin the swimlane one.
• Mermaid with a config header could not be converted: the converter treated the front matter's --- as the header and the tail of a multi-line %%{init}%% as a statement. Both are skipped now.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.12.5_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.12.4 turns "Format source" from an empty button into a real formatter.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• The Format button / Shift+Alt+F now actually reformats the source, no longer just trimming trailing whitespace:
• Mermaid: subgraph…end, sequence loop/alt/opt/par/rect/critical/break/box…end, else/and/option, and class / state / er braces are all indented to 4 spaces;
• Graphviz DOT: lexer-level layout — one statement per line, attribute lists inlined, subgraphs indented; a one-liner like digraph G{a->b;b->c} expands into readable lines;
• D2: brace levels are indented to 2 spaces.
• Whitespace only, semantics untouched: strings, HTML labels, multi-line quoted labels, Mermaid YAML frontmatter and D2 |md block strings are preserved byte for byte; DOT comments and # lines are carried over verbatim.
• No fake "formatted": when the source is already canonical, the status bar says so and the document is not marked dirty.
• Undoable: the whole-document replacement goes through the editor's normal transaction, so Ctrl+Z returns to the pre-format text; saving still follows your auto-save setting.

Fixes

• "Format source" was never really implemented: the button and Shift+Alt+F only trimmed trailing whitespace, so on most documents they did nothing. This release adds the Rust-side formatter and wires it to the button, the shortcut and the command palette.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.12.4_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.12.3 turns palette colors from an invisible view state into visible source text.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• Picking a palette edits the source: choosing a scheme in the preview toolbar writes the palette block into the source immediately, so the editor and the render show the same thing. Saving follows your auto-save setting — the old "colors are preview-only, bake them later" split is gone.
• Portable colors: mermaid live, GitHub rendering and editor plugins show the colors directly.
• Unsaved documents remember too: the choice is no longer sidecar state keyed by file path.
• Opening a file never dirties it: the palette guessed from the diagram is only a suggestion.
• Migration: documents that had a remembered scheme but no block get one written into the buffer on first open (unsaved, undoable).
• After AI apply or a format conversion the palette block is restored automatically, so colors never vanish.

Fixes

• The row-tint button gave no state feedback: it toggled the setting but had no pressed style. It now shows an accent background when on, with aria-pressed for accessibility.
• Missing separator in the palette menu between the scheme list (including "None") and the actions.

Notes

• Switching theme does not recolor: the block is a snapshot for the theme active when you picked it (its header says light or dark). Use the new "Regenerate for current theme" action after switching.
• "Default palette" in settings now only applies to new documents; existing files pick their own.
• Documents that only ever "followed the default" will show no colors after upgrading — pick a scheme once and it becomes part of the file.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.12.3_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.12.2 teaches auto-coloring where a node lives, not just what it is (entry / decision / data / external / risk).

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• Color by region: Mermaid subgraphs, DOT clusters and D2 containers are now grouping keys — nodes inside a block share a hue, different blocks get different hues (up to nine, so a diagram with 22 subgraphs still reads clearly).
• Frames get tinted too: each block's border gets the same hue, one step lighter than its nodes, so the region is obvious and the nodes still stand out.
• Semantic roles win: decision / entry / data / external / risk still override the group color — "something goes wrong here" is never swallowed by a region tint. Grouping only colors plain nodes.
• No more flatness: in real architecture diagrams 70–80% of nodes are plain, and they all used to collapse into one color; now they separate by subsystem, without touching the palette itself.
• Wrapper blocks that only contain other blocks also get their own tint instead of staying default yellow.

Fixes

• Nothing got colored after clearing by hand: any leftover custom class name used to count as "already colored", so deleting the classDef lines (the most natural way to clear) left :::catalog markers behind and roughly 80% of nodes were silently skipped. Now only a class that actually sets a fill counts as a hand-picked color.
• Phantom nodes in D2 files: fill: / stroke-width: / shape: inside classes: { … } were parsed as nodes and styled at the end of the file; those blocks are skipped now, and inline {class: …} is parsed.
• Label guesses overriding structure: layered diagrams have "data" in almost every label, which painted a whole chart in one violet. Priority is now explicit role > shape > group > label > main.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.12.2_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.12.1 brings the palette into the source pane: you can see which lines will be coloured, without switching to the diagram.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• A swatch on the line where each node appears — every node that will be coloured gets a swatch on the left of its first line, in exactly the colour it will render with (computed by the backend with the same rules the renderer uses, not guessed in the front end). One swatch per node, so long diagrams stay readable.
• Hand-written colours are visible too — a node carrying its own style / fillcolor (and therefore skipped) gets a dashed frame and a "hand-written, kept" tooltip, so it never looks like it will be recoloured.
• Hover to inspect — A · entry plus #d4e3ed / #4ab5a0: role and value, without opening the preview.
• Row tint (off by default) — a new "Tint rows" button next to Format, and the same switch under Settings → Editor. It paints a very faint role colour behind the text, so code never looks washed out, and it never touches the document.
• The overlays are read-only — no undo entries, no file changes, no dirty flag.

Fixes

• The edge switch no longer bakes colours into the buffer — in 3.12.0 toggling "edges follow the palette" wrote the palette into the document body and marked it dirty, contradicting the preview-only model; it now only redraws (the status line says "preview updated, source untouched").
• Two adjacent notes in Settings → Editor were touching; they now have a gap.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.12.1_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.12.0 adds automatic colouring: the AI no longer invents hex values, it only tags roles; the app expands them into a palette — reproducible, swappable in one click, and optionally preview-only.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• The AI tags roles, the app picks the colours — the model writes main / entry / decision / data / external / failure / note, and the palette expands those into values: the same sentence never yields two different palettes, and dark themes get the brighter ladder automatically. The same tags work in Mermaid, DOT and D2.
• Six schemes plus a wireframe one — Pine / Indigo / Lotus / Olive / Ochre / Tungsten (achromatic, for wireframes and print). Switch from the third control in the preview toolbar; the choice is remembered per file, and edges follow the scheme too (switchable in Settings).
• Picked on open — a file with no remembered scheme gets one chosen locally from its role mix and labels (data-heavy → Indigo, failures → Ochre, many external calls → Olive, UI wording → Lotus, otherwise Pine), with the reason shown in the status bar. New documents start with None.
• Colours live in the preview — switching scheme or theme never rewrites the source; 「Bake into source」 is there when you want the colours in the file. Clearing (「None」) only touches the buffer, too — saving stays your call.
• 「None」 tries to leave nothing behind — our own block goes first; if hand-written or foreign colours remain and a model is configured, the model strips colours only (and the cleanup is discarded if it changes the structure).
• Quieter diagrams — edges follow the scheme at reduced saturation, and the schemes were re-spaced by measured distance (role fills went from ΔE 1.2 to 3.6–5.9, scheme-to-scheme from 2 to 17).

Fixes

• Mermaid class names containing hyphens (A[开始]:::my-class --> B) no longer break the whole file.
• A node mentioned again on an edge keeps its shape (decision/cylinder nodes were being treated as main path).
• A failed palette expansion no longer blocks rendering: the diagram still draws and the reason lands in the status bar.
• The README screenshots no longer show an ELK "failed to load" message (the capture script now serves the bundled ELK chunk).

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.12.0_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.11.3 moves two everyday things forward: Mermaid diagrams now use the ELK layout by default, and diagram files can be opened by dropping them onto the window.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• Mermaid defaults to the ELK layout: layered diagrams get cleaner edges with fewer crossings. The layout engine ships offline and is warmed up after start-up, so the first render does not wait. Switch back any time from the preview toolbar ("Layout · elk" → dagre); the choice is remembered per file.
• Drop files to open: drag .mmd / .mermaid / .dot / .gv / .d2 / .drawio / .excalidraw onto the window and release. A full-window hint appears while dragging; the file opens as a tab. Dropping onto the AI panel on the right still attaches the file as conversation context — the drop target decides.
• Unsupported files are called out: dropping an image or an archive no longer produces a tab full of parse errors; the status bar tells you how many files were ignored.

Fixes

• Dropping folders or non-diagram files no longer opens a "fell back to Mermaid" tab with a screen of parser errors.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.11.3_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.11.2 reorganizes the AI page in Settings: one long form becomes four groups, and the difference between official and custom SystemOne is finally visible at a glance.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• Four AI setting groups: Text & image models / Intent / Behavior / Memory. No more hunting down a single long form.
• Text & image models: default model, gateway status, and BYOK provider cards in one place, with breathing room between the gateway note and the Add-provider row.
• Intent: four mode cards (Auto / Official / Custom / Off). Official mode shows membership details read-only and needs no local key; only Custom expands endpoint, model, and key.
• Test classification: send one fixed sentence from the Intent page and see intent, confidence, model, and latency; the test button is disabled when intent is off.
• Custom timeout: raised from 2s to 15s for TypeSafe and other proxied endpoints.
• Behavior / Memory: switches grouped by purpose; memory counts and the manage action are together.

Fixes

• The gateway status block and the Add-provider button were touching; they now have a 12px gap.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.11.2_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.11.1 makes SystemOne part of membership: signed-in members use the official classifier by default, while custom providers remain available. The conversation schema also gets a one-way normalization.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• Official SystemOne: signed-in members classify intents through Diagramon's official service by default, with no local key to configure.
• Custom still available: Settings offers Auto / Official / Custom / Off; an explicit custom choice is not overwritten by signing in.
• No key exposure in official mode: it calls the server with the login token and never reads the local classifier key. Failures, signed-out state and non-member state all fall back to local rules without blocking sending.
• Cleaner auto status: “Auto-detected + confidence” appears only on a successful verdict; when disabled, timed out or unclassified the status disappears instead of showing “fallback”.
• Normalized conversation schema: turns store only intent; legacy tab fields are migrated on read, so history no longer depends on the removed tab concept.
• Cheaper classification: no request while the panel is collapsed; concurrent classification of the same sentence shares one request; changing endpoint/model/thresholds invalidates old verdicts.

Fixes

• The automatic render-fix turn referenced the removed retryCtx.tab, losing its intent marker.
• Double-clicking Send during intent classification could fire the same sentence twice; Send is now locked during classification.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.11.1_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.11.0 reworks the AI panel: conversations are no longer split across tabs but form one continuous timeline. Each message shows — and lets you change — its intent before sending, while automatic classification appears only when there is an actual verdict.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• One timeline: Generate, Vision, Review and Explain no longer own separate tabs; a document's conversation is one chronological history, so review and retry face a single record.
• Four-way intent slider: see each message's intent before sending. Click any stop to override, click “Auto” to return. The override clears after sending, so the next sentence is classified anew.
• Auto status only with a verdict: “Auto-detected 86%” appears only when classification succeeds. When disabled, unconfigured, timed out or low-confidence, the status disappears instead of showing a confusing “fallback” label.
• Output format selector: Follow current / Mermaid / Graphviz DOT / D2 / drawio / Excalidraw. When the target differs from the current document, applying opens a new tab in that format. drawio and Excalidraw are converted from Mermaid by the carrier's importer.
• Vision stays a hard rule: an attached image means Vision; no active document means Generate. Neither is left to the classifier.
• Explain stays read-only: its empty state keeps the primary action and three angle chips; replies produce no code card and never write to the document.
• Cheaper classification: no request while the panel is collapsed; concurrent classification of the same sentence shares one request; changing endpoint/model/thresholds invalidates old verdicts.
• Normalized conversation schema: turns now store only intent; legacy tab fields are read and migrated automatically, so history no longer depends on the removed tab concept.

Fixes

• Double-clicking Send while intent classification was still in flight could fire the same sentence twice (two billable calls). Send is now locked during classification.
• The automatic render-fix turn referenced the removed retryCtx.tab, losing its intent marker.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.11.0_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.10.8 adds sorting to the Explorer file tree: by name or last-modified time, in either direction, plus a folders-first toggle. The choice is saved with your settings.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• Explorer sorting: a sort control in the tree header now offers “Name A→Z / Z→A” and “Last modified, newest / oldest first”, applied at every level.
• Folders first: directories come before files by default; turn it off to mix them under the same ordering.
• Modified time shown while time sorting: rows display their timestamp only in time mode, so name sorting keeps its full width. A folder uses the newest modified time in its subtree, so recently changed folders float up.
• State always visible: the stats line shows the current sort and opens the same menu; the header button turns accent-coloured when the order is not the default.
• Saved preference: sort order and folders-first persist across restarts.
• Chinese names sort by pinyin, and numbers compare numerically (“图 2” before “图 10”).

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.10.8_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.10.7 unifies message copying in the AI panel as icon buttons: copy AI replies and your own input with one click, in exactly the same style as the edit-and-resend / regenerate buttons — and fixes those buttons doing nothing on your own messages.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• “Copy source” on AI replies is now an icon button: the label moved to title / aria-label, so the message header is no longer crowded. Clicking still copies all source produced by that reply (or the prose when there is no code block).
• One-click copy for your own messages: the “me” message header now has the same copy icon; one click puts your input on the clipboard — no more selecting text by hand.
• The copy button now matches the neighbouring action buttons exactly: copy, edit-and-resend / regenerate, and delete all live in one button group with the same size, spacing, and hover reveal (copy used to stay fully opaque with different padding, looking like a different control). Tooltips still read “Copy source” / “Copy input”; success shows “Copied”, and clipboard failures are still reported honestly.
• Fixed “Edit and resend” / “Delete this turn” doing nothing on your own messages: newly sent user messages were missing their tab marker, so the buttons could not locate the turn. Both now work — the original text goes back into the input, or the whole turn is deleted as a pair.
• Includes the previous two fixes: the Mermaid dashed-link fix from 3.10.6 and the Explain Markdown preview/source toggle from 3.10.5.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.10.7_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.10.6 is a fix release: -.-> and linkStyle dashed edges are no longer turned solid at crossings.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• Dashed edges no longer render solid: Mermaid 12.2.0 draws “line hops” where edges cross, and its post-processing rewrites every edge that has a hop with the solid-line stroke-dasharray. That wiped out both -.-> and linkStyle … stroke-dasharray styles. Line hops are now disabled so the line pattern — which carries meaning — always wins.
• No more line-hop arcs at crossings: the trade-off of this fix. Hops are decorative; dashed vs solid expresses the relationship. Until upstream fixes the overwrite, correctness comes first.
• Includes the 3.10.5 Explain Markdown preview: Explain replies render Markdown by default with a per-reply Source toggle (this release also brings it to users still on 3.10.4 or earlier).

Fixes

• -.-> and custom linkStyle dashes no longer become solid (reported 2026-10-27: the same script renders dashed on mermaid.ai/live but solid in Diagramon). Root cause: Mermaid 12.2.0's line-hops post-processing overwrites the edge stroke-dasharray; a regression assertion now checks that four AI edges keep their 6 4 dash in ui_probe.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.10.6_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.10.5 makes the Explain output actually readable as Markdown: preview by default, one click to the raw source.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• Explain replies now render Markdown by default: headings, ordered/bullet lists, bold, inline code, quotes, rules, tables and links are formatted instead of showing raw ###, ** and | --- |.
• Per-reply Preview / Source toggle: switch to Source to read or copy the model's original Markdown. The switch redraws only that reply, so a long conversation does not jump to the bottom.
• Streaming renders as it arrives: the reply updates in the selected view while it is still being generated — no need to wait for the end of the message.
• The view sticks to the message: switching tabs, documents or re-rendering keeps your choice, and Explain turns restored from disk also open in Preview.
• Rendering is safe: model output is treated as plain text, inline HTML/scripts are never executed, javascript: links are never clickable, and images keep only their alt text so a preview never makes a network request. External links are handed to the system browser only when clicked.

Fixes

• Explain no longer shows Markdown markers literally: the previous release returned Markdown but displayed it as plain text; it now renders a preview by default, with the original one click away.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.10.5_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.10.4 turns "read this diagram" into the AI panel's first read-only tab, and lets the view refit itself when the render area changes size.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• New "Explain" tab (the 4th tab in the AI panel): a read-only reading of the current diagram — what it describes, how the main path flows, where the module boundaries are, which error branches or design risks deserve attention. No code output, no Apply button, no edits to the document. Replies live in this tab's own conversation, persisted per document and listed in History.
• Four direct entry points, all landing on the same action:
• AI menu → "Explain: read-only read of the current diagram"
• shortcut Ctrl+Shift+E
• command palette (Ctrl+Shift+P) → "Explain…"
• the "Explain" button in the preview header, or right-click a document tab → "Explain (read-only)" The empty state adds a primary button and three angle chips (what it says / main path / risks) that send directly.
• Ctrl+Shift+E also works with the panel collapsed: it opens the panel, switches to Explain and starts the reading.
• Auto-fit when the render area resizes (new setting, on by default, under Settings → Editor): after dragging the splitter, toggling the sidebar / AI panel / bottom panel, switching view modes or resizing the window, the diagram refits and re-centres exactly as pressing "Fit view" would. Turn it off and the viewport only changes on open/switch and on an explicit fit.
• AI tab renamed: "Chat generation" is now "Generate", matching the four actions Generate / Vision / Review / Explain.

Fixes

• "Explain what this diagram is about" no longer draws a diagram: the suggestion chip under the Generate tab used to only fill the input box, and the request went out with the "draw a diagram" intent; it now jumps to the Explain tab and sends with the read-only intent.
• Restored conversations retry with the right intent: turns loaded from disk used to lose their tab, so retrying a Review turn was sent as "generate from scratch"; they are restored with their tab now.
• The diagram no longer ends up half out of view after a resize: narrowing a panel or enlarging the window used to leave the old zoom in place; it now refits and re-centres on the new viewport (can be turned off, see above).

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.10.4_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.10.3 fixes two things: AI edits corrupting your document, and the app writing to disk without your consent.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still works in the portable build, but updates are delivered as the installer (it never patches the portable folder in place) — download the new ZIP to keep using it.

Highlights

• AI edits no longer return half a diagram. "Apply to editor" replaces the whole body with the code block from the reply, while the review prompt used to say "don't rewrite the diagram… don't repeat the source" — so the model returned a diff or fragment, which broke the document and the Mermaid parse. Both sides now work on the full text: the whole source is sent, and the model must return the complete modified source (untouched parts kept verbatim).
• "Ask AI to edit this selection" also sends the full document. Previously only the selection went up as context, and applying left the file with just that fragment. The selection is now only an instruction ("change only this part"); the full source still goes up and comes back complete.
• Apply takes the last code block. Models often print one version and then a corrected one; apply used to take the first block. It now matches the internal extractor (last non-empty fence).
• Autosave is off by default. Writing to disk is irreversible (AI apply and bulk edits change the body), so a silent autosave is the app pressing Ctrl+S for you. Files are now written only on Ctrl+S / Save As; turn Settings → Editor → Autosave on for the old behaviour (delay 500–60000 ms). Upgrading will not silently turn off autosave you had explicitly enabled — it is treated as off only when the setting is absent.

Fixes

• Low Mermaid parse success after AI edits: the prompt steered the model into returning only the diff.
• "Ask AI to edit this selection" truncated the document to the selection on apply.
• The Settings autosave switch showed "on" when the field was missing, disagreeing with the default.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.10.3_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.10.2 is the release where the documentation matches the code: conversion order, menu wording and both help reference pages are now aligned with what actually ships — and the shortcuts that were only printed in menus finally work.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still works in the portable build, but updates are delivered as the installer (it never patches the portable folder in place) — download the new ZIP to keep using it.

Highlights

• One display order everywhere: drawio → Mermaid → Excalidraw → Graphviz DOT → D2. The New submenu, the tab-bar Convert dropdown, the Conversion reference list and matrix, and the command palette all read that single order — no more "dropdown says one thing, the reference says another".
• The Convert dropdown now matches the reference line by line. For a Mermaid source both read drawio → Excalidraw → DOT → D2.
• Shortcuts are actually wired: Ctrl+K Ctrl+T (toggle theme) and Ctrl+K Ctrl+S (shortcut reference) were printed in menus but did nothing; they now work as VS Code-style chords, and Shift+Alt+F (format source) gained its missing binding.
• The shortcut reference was rewritten against the implementation: the Alt+1…Alt+5 claim is corrected (Alt+1 Explorer / Alt+2 focus search / Alt+4 cloud documents / Alt+5 outline), and Ctrl+R (file history), Ctrl+Tab / Ctrl+Shift+Tab (cycle tabs), Ctrl+Shift+C (copy preview) and Ctrl+Q (quit) are now listed; the sidebar description matches today's views.
• Menu wording tightened: Help has Shortcut reference / User guide and three uniformly named format docs; View has Settings…, Source only / Split / Preview only, Full-screen preview; File has Search in workspace and Open history…, and submenu entries no longer carry a misleading ellipsis.
• User guide corrected: the conversion section now states the real directions (DOT → D2 never existed; DOT → Mermaid is experimental) and points unavailable directions to Help → Conversion reference; the AI section documents the read-only "explain this diagram" usage.

Fixes

• The Conversion reference no longer says "(read-only)" — it only ever explains capabilities, and the two extra words made it look like a second action entry.
• The Convert dropdown and the reference page used different orders for the same source.
• Three descriptions in the shortcut reference disagreed with the code (chords, activity-bar views, sidebar view list).

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.10.2_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.10.1 is a UI consolidation release: search no longer has its own sidebar view, conversion keeps a single action entry in the tab bar, and the capability reference now lives in Help.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still works in the portable build, but updates are delivered as the installer (it never patches the portable folder in place) — download the new ZIP to keep using it.

Changes

• Search is now part of Explorer. A content search field is always available at the top of Explorer: a non-empty query replaces the file tree with grouped results, and clearing it restores the tree. Regex, case sensitivity, debounce, stop and result navigation are unchanged. The separate search activity icon is gone; Alt+2 / Ctrl+Shift+H focus the field directly.
• One conversion entry. The activity-bar and sidebar conversion centers are removed, along with duplicate entries in the File menu, status bar and tab menu. Conversion runs from the tab bar's Convert button (Alt+Shift+C still works). The status-bar format item is now read-only.
• Conversion reference moved to Help. A new read-only Help → Conversion reference… dialog combines the old sidebar matrix and the settings “Formats & Conversion” page: format registry, every direction, availability and reasons. It has no action buttons.
• Settings no longer has a “Formats & Conversion” tab. That page was read-only; its content now lives in the Help reference.
• AI tab divider. A 1px divider now separates Generate / Vision / Review from the message stream, matching the source/preview tab bar.

Fixes

• Persisted sidebar_view = search / convert values are migrated to Explorer on upgrade, so the sidebar no longer comes up blank.
• Removed duplicate conversion entries and the mixed “reference vs. action center” responsibility.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.10.1_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.10.0 closes the gaps between what the AI panel promised and what it did: explain a diagram, paste two images for comparison, retry a single turn, and land directly on Review when a diagram is already open.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still works in the portable build, but updates are delivered as the installer (it never patches the portable folder in place) — download the new ZIP to keep using it.

Highlights

• Explain: read-only analysis of the current diagram. The empty-state action now uses a dedicated Explain intent. It returns the business context, happy path, module boundaries, error branches and risks — no code fences and no Apply button, so explaining a diagram can no longer overwrite it.
• Vision: paste with Ctrl+V, drag files in, and compare two images. Paste a screenshot straight into the Vision dialog, or drop files; up to two images, in upload order. The dialog shows how many are selected and both thumbnails remain in the chat. Images stay in memory — never written to disk or conversation history.
• Single-turn actions: retry, edit & resend, delete. No need to clear a conversation to fix one prompt. A retry records the gateway ledger row and sends Retry-Of on the next call.
• Opening the AI panel with a diagram open now lands on Review. The source-selection “Ask AI to edit this” action also goes to Review instead of Generate; an explicitly chosen tab is still kept.
• Cloud gateway auto tier: choose “Auto tier” in the model menu and the server routes by capability and image-input needs.
• Gateway attribution headers: scene and retry_of are sent with gateway requests only; BYOK requests never receive these internal metadata headers.
• More readable conversion log: AI-enhanced conversions are labelled, with distinct states for success, early stop, local fallback, cancellation and failure; rows with a target document open it.

Fixes

• A second pasted image no longer replaces the first, and both thumbnails are kept.
• The AI panel no longer stays on Generate when a diagram is already open.
• Single-turn actions now have visible, accessible entry points; retries can be tied back to the original gateway call.
• Explain no longer produces code blocks or exposes an Apply action.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.10.0_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.9.2 adds a safety net to conversion: when the result is lossy or outright fails, your own configured model can repair it — and a count check decides whether the repair actually worked.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still works in the portable build, but updates are delivered as the installer (it never patches the portable folder in place) — download the new ZIP to keep using it.

Highlights

• AI-assisted conversion (optional, off by default). The entry appears only when it applies: the conversion is lossy or failed, a model is configured, and the target is a text format. One initial rewrite plus at most 3 correction rounds, with "attempt N / M left" progress; two identical failures in a row stop early so you do not burn quota. Success opens a new tab; failure keeps the local result and says so — never an empty tab. The first run shows exactly what will be sent (cancellable), and calls count toward your AI usage.
• A count check after every conversion. Nodes and connections are counted and compared; if the result is short you get "N nodes / M connections missing". A shortfall on text targets counts as a failure (and can be fed back to the model); on drawio / Excalidraw it is an engine expressiveness gap, so it is only reported. When one side cannot be counted, it says so instead of pretending to match.
• One validation layer for all five formats: Mermaid / DOT report real line and column, D2 actually compiles with the bundled wasm, drawio / Excalidraw get structural checks. When an engine is not ready or a file is very large, the result is explicitly marked degraded — "not validated" is never reported as "passed".
• New setting: "Allow AI enhancement when conversion is lossy (off by default)", with the entry conditions and quota note.

Fixes

• Mermaid → DOT / D2 no longer dies on common syntax: longer connectors (===>, --->, -..->), A --> B & C multi-target edges, subgraph id ["title"], and edges that connect subgraphs all convert now. Such files used to fail as a whole at the offending line.
• No more phantom nodes for container-to-container edges: subgraph → subgraph links are clipped to the cluster border.
• Errors in the conversion dialog can be copied: the text is selectable and there is a Copy button; the same applies to fidelity notes and the footer text.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.9.2_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.9.1 fixes 3.9.0: syntax errors now really show and jump to line + column.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11.

Fixes

• The problems panel now really shows line + column. In 3.9.0 the exact column reported by the engine was collected but never displayed, and clicking only jumped to the start of the line.
• A rough same-line result no longer hides the precise one. Previously, if the line scanner also reported that line (e.g. "bracket not closed"), the engine's precise result with real line/column was dropped. The engine now wins on the same line.
• Clicking an issue jumps to line:column, not just the line start.
• Other lines unchanged: scanner-only findings are still reported, and valid documents are still not flagged.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.9.1_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.9.0 makes "going to the spot" actually work: syntax problems now report real line and column numbers, and clicking an entry in the outline jumps to that element in the source.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• Real line and column numbers for syntax errors: Mermaid and Graphviz DOT problems are now parsed by the graphics engine itself, which reports the actual line (and column for Mermaid) shown in the problems panel. Previously it could only say "something looks wrong on this line".
• Click the text outline to jump: in the sidebar outline for Mermaid / DOT / D2, clicking a node or edge moves the caret to that element in the source and scrolls it into view.
• No false alarms: when the engine is unavailable, or the document is very large (over 5,000 lines), engine validation is skipped — better to report less than to report wrongly. Valid documents are not flagged.
• No extra dependencies: it reuses the rendering engines already shipped in the app. No Node.js install, no increase in installer size.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.9.0_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.8.16 is a steady-state update: a heads-up before opening large diagrams, a structure outline for canvas documents, and a fix for the upgrade that could not stop the running app.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• A heads-up before large diagrams: opening or saving a diagram above 400 KB / 5,000 lines now asks first ("this diagram is large, preview may lag for a few seconds"). You can continue or cancel, and the same document/action is only asked once per session.
• Structure outline for canvas documents: drawio / Excalidraw documents now show their groups and shapes in the sidebar Outline view; groups collapse and expand, and clicking a node selects and centers it on the canvas.
• More reliable conversion and canvas: conversion defects fixed in recent releases are now locked in as regression fixtures, and the "convert twice / switch tabs" canvas leakage has automated coverage.
• Layout engines are reused: Mermaid / Graphviz / D2 layout instances stay resident, so opening several diagrams no longer re-initialises them each time.

Fixes

• Fixed the upgrade from 3.8.14 failing because the installer could not stop a running Diagramon process. The installer now ends the old process before overwriting files.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.8.16_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.8.15 fixes a conversion defect seen in a real case: diagrams that use the A("label<br>(IP)") rounded-node idiom came out garbled when converted to drawio — they now convert cleanly.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• Rounded nodes whose labels contain parentheses no longer garble the whole diagram: Mermaid lets you write A("label<br>(172.16.0.1)") — parenthesis inside a rounded node. Converting that to drawio used to trip the importer (labels shredded, fragments leaking into the next node, geometry in chaos). Those rounded nodes are now treated as stadium shapes before conversion, so the output is clean and complete.
• Measured on this deployment diagram: about half the nodes were garbled before; after the change, zero broken labels and every child vertex lands inside its parent box.

Fixes

• Mermaid → drawio: nodes using a rounded shape A("label (IP)") with parentheses in the label garbled the diagram: drawio's built-in importer can't parse such a shape — its paren matching goes off. Conversion now rewrites only rounded labels that actually contain ( / ) to A(["..."]) (the closest usable double-round shape); paren-free rounded nodes are left untouched, and a fidelity note is added. A regression test covering the real corpus was added (confirming paren-free rounded, rectangle and subroutine shapes are unaffected).

Notes

• Top-level subgraph cluster bounding boxes may still overlap each other after conversion to drawio — an inherent limitation of drawio's importer's subgraph grouping, not a regression of this fix; it can later be eased with the existing "ELK re-layout" option.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.8.15_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.8.14 fixes two conversion defects: Mermaid files that assign style classes inline now convert to DOT / D2, and diagrams with subgraph blocks no longer collapse into a single non-editable image when converted to Excalidraw.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• Diagrams with groups are finally editable in Excalidraw: any diagram using subgraph blocks used to convert into a single static image — it looked right, but nothing could be dragged. It now comes through as real shapes. Measured on a 148-line deployment diagram: 1 image element before, 181 editable elements after (59 boxes + 34 arrows + 88 text runs).
• Inline style classes no longer break a whole file: Mermaid lets you attach a class right on a node (A[text]:::someClass). That used to make Mermaid → DOT / D2 fail outright with "trailing unparsed content on line N". It is now understood, and the styling comes across too.

Fixes

• :::class inline class made Mermaid → DOT / D2 fail: the parser only understood id[label] and treated the trailing :::class as leftover text, failing the whole file. Both spellings are now equivalent: ::: is read (including :::a,b for several classes) and behaves exactly like a separate class A someClass statement. The styling is migrated (DOT gets all of them; D2's .class holds one, so the first is used and the conversion record says so).
• Mermaid → Excalidraw with subgraph degraded to a bitmap: the upstream converter looked up the group element by its bare id, while the rendered id carries a per-render numeric prefix — so the lookup always missed, threw, and was caught into a whole-diagram image fallback. Conversion now retries the lookup by id suffix, so groups come through correctly; the fallback is removed as soon as the conversion finishes and does not affect anything else.

Notes

• The Excalidraw bundle and its Mermaid converter were bumped together (mermaid-to-excalidraw 2.3.0).
• Two canvas probes gained an opt-in flag for restricted sessions (DGM_PROBE_NO_SANDBOX=1). Development and acceptance tooling only — the product itself is unaffected.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.8.14_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.8.13 adds a "Re-layout with ELK" option when converting to drawio: with it on, drawio's own ELK layered engine arranges the diagram, cutting back-edge detours and edge crossings noticeably.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• Try a different layout engine right in the conversion dialog: Mermaid → drawio now has a "Re-layout with ELK" switch. With it on, drawio's own ELK layered engine arranges the diagram — back edges stop taking the long way round and edge crossings drop, so medium-sized flowcharts land much closer to a hand-tuned result than the default dagre. The switch remembers your choice.
• Off by default, so nothing changes unless you ask: unchecked, it is exactly the old dagre path.
• When it does not apply, you are told: the conversion record says what actually happened — applied, the source already declared layout: elk, the source already had a config block (injecting another would duplicate a key, so it was skipped), or the target is not a flowchart. None of these are silent.

Fixes

• Canvas did not refresh from the second conversion on: converting two files to drawio (or Excalidraw) in a row left the second tab showing the first diagram; switching between two canvas tabs had the same problem. The readiness flag was cleared when switching documents, while the host page only sends that signal once at startup, so later load commands sat in the queue forever. Fixed (shipped together in 3.8.13).
• Stale pending payload after closing a canvas tab: closing the last canvas tab of a format now also drops that pending conversion payload, so a new document of the same format cannot inherit it.

Notes

• "Re-layout with ELK" only applies to Mermaid → drawio flowcharts: ELK lives inside drawio's importer, and the Excalidraw chain uses a different importer that does not read this config.
• It does not change what document-level layout means — the layout you pick in the preview is still the preview's business; conversion follows this switch.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.8.13_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.

Diagramon 3.8.12 fixes a canvas-hosting defect: converting two different files to drawio (or Excalidraw) one after another left the second canvas showing the first file's content.

Downloads

About the portable build: it ships diagramon.exe + WebView2Loader.dll + ui\ + assets\, and those must stay together (the ui\ and assets\ trees are read from disk, not embedded in the exe). It needs nothing extra installed: no Node.js, no Chrome, no VC++ redistributable (the CRT is statically linked) — only the system WebView2 runtime that comes with Windows 10/11. "Check for updates" still finds new versions, but updating downloads the installer (it does not replace the portable folder in place) — to stay portable, grab the new ZIP manually.

Highlights

• No more cross-wired conversions: open two Mermaid files and convert them to drawio in turn — the second tab now shows its own diagram instead of the first one. The readiness check was wrong: switching documents cleared the "ready" flag, but the host page only sends that signal once at startup, so the second load command sat in the queue and never went out.
• Switching between tabs is fixed too: the same mis-set flag also made switching between two drawio tabs show the wrong diagram.
• Nothing left behind after closing a tab: closing the last canvas tab of a format now also drops that pending conversion payload, so a newly created document of the same format cannot be filled with it.

Fixes

• Second conversion to drawio / Excalidraw did not update the canvas: from the second load onward the command was parked in the outbound queue forever and the canvas kept the previous document. Readiness is now set only when the host page reports it, and switching documents no longer clears it.
• Switching between canvas tabs showed the wrong diagram: same root cause (readiness wrongly cleared), the canvas did not reload the document body after a tab switch.
• Stale pending payload after closing a canvas tab: the pending conversion payload is keyed by format and is a singleton; it was not cleared when the host instance went away, so the next document of that format could be mistaken for a conversion and filled with old content. It is now cleared with the host.

About Diagramon

Diagramon is a local-first multi-format diagram editor: Mermaid, Graphviz DOT, drawio and Excalidraw can all be edited with live preview, with AI assistance for generation, review and image recognition. Rendering and validation work with no network at all — code or images reach a model only when you actively use AI, and then only the endpoint you chose.

Official website: https://www.diagramon.com

Requirements

• Windows 10 / 11 64-bit
• WebView2 runtime (normally pre-installed on Windows 10/11; the installer downloads it if missing)
• No Node.js, Chrome or VC++ redistributable needed — the canvas runtimes and front-end assets all ship inside the installer

Install and update

Download Diagramon_3.8.12_x64-setup.exe and run it. Users on an older version will be offered this release via Help → Check for updates (the update package is this same installer; its signature is in latest.json).

This installer is not yet Authenticode-signed, so Windows SmartScreen may show a warning.