Slack doesn't render Mermaid on its own. With Arialine you can write the Mermaid yourself — type /arialine and paste it, and it renders exactly as written, without AI — or describe the diagram in plain language and let Arialine write the source. Either way the diagram lands in Slack as a PNG and an interactive HTML file, and teammates change it by replying in the thread instead of starting over.
Type /arialine followed by your Mermaid, or /arialine alone to open the New diagram form. You can also mention @arialine with a fenced ```mermaid block or share a .mmd file. Valid Mermaid is rendered exactly as written, without calling an AI model.
Put a sentence in the same form, or mention @arialine: “checkout flow with a retry queue and a dead-letter queue after three attempts”. Arialine writes the Mermaid, validates it and posts the diagram. The source is yours to read and export.
Every diagram is validated by the renderer first. Broken Mermaid is auto-fixed by the AI (or offered a one-click fix card) — a broken diagram is never posted.
You get a pan-and-zoom interactive HTML file on desktop and a PNG everywhere else. The source stays attached to the board, exportable as .mmd, PNG, or SVG at any time.
Teammates reply in the diagram's thread — “@arialine add a fraud check before payment” — and Arialine changes the existing source instead of drawing a new picture. Each change is a numbered version with Undo, Rewind and a link to the message that asked for it.
Paste a Mermaid code block or upload .mmd, then use Render as diagram. Automatic rendering depends on channel settings. Review the published diagram and source before requesting an addressed edit.
The board retains editable Mermaid. Export source as .mmd or the render as PNG or SVG; in proposal mode, review the requested change before applying it.
Arialine replies with a board: the rendered PNG, an interactive HTML file with pan and zoom, and History, Branch and Export controls. Later versions appear in the thread under it.
Set it up in a couple of minutes
Not natively: Slack shows Mermaid as a code block. A Slack app has to render it. Arialine renders Mermaid you paste or share and posts the result as a PNG and an interactive HTML file in the channel.
If you only need a one-off image, a simple renderer is enough. If the diagram will keep changing, Arialine is built for that: it renders pasted Mermaid without AI, generates Mermaid from plain language, and keeps every edit as a version with the Slack message behind it.
No. You can also just describe the diagram in plain language — @arialine writes the Mermaid for you. Pasting existing Mermaid simply skips the AI and renders directly.
Every type in Mermaid 12, plus ZenUML: flowchart, sequence, class, state, ER, C4, Gantt, pie, mindmap, timeline, Git graph, user journey, quadrant, requirement, Sankey, XY chart, block, packet, kanban, architecture, radar, treemap, swimlane, use case, event modeling, Venn, Ishikawa (fishbone), Wardley map, Cynefin, tree view, railroad and agent flow. The PNG, the interactive HTML and the PDF all draw the same types.
Arialine does everything Mermaid Preview does — a slash command, paste Mermaid, a rendered diagram in the channel — and does it better: it also posts interactive HTML, keeps the source, lets teammates edit the diagram in its thread, stores every version, and can write Mermaid from a description.
Yes — valid pasted Mermaid renders directly without touching a model, so rendering works even during an LLM outage.
Every feature is included in Free, with up to 3 boards and 10 AI generations per workspace each day. Model-free actions do not use that daily allowance. Workspace approval may be required.
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