About
Arialine is the Mermaid diagram tool and AI diagram generator for Slack. Create, edit and version flowcharts, sequence diagrams, C4 architecture diagrams, ER diagrams and Gantt charts without leaving Slack. Slack does not render Mermaid on its own; Arialine adds Mermaid rendering, AI diagram generation and diagram version control to every Slack workspace, including Slack Free.
Mermaid in Slack: type /arialine and paste Mermaid code. Valid Mermaid renders exactly as written, with no AI and no quota, as a PNG and an interactive HTML diagram in the channel. Or mention @Arialine with a Mermaid code block, upload a .mmd file, or use the Render as diagram message shortcut. The Mermaid source is kept, so every diagram stays editable.
AI diagram generator for Slack: describe the diagram in plain language, for example "@Arialine sequence diagram for OAuth login with 2FA". Arialine writes the Mermaid and posts an editable diagram. Write "@Arialine diagram what we decided" and recent channel discussion becomes the diagram.
Edit by replying in the thread: "@Arialine add a retry step after Payment" creates a new version linked to the Slack message, author and date behind it, with undo, rewind and branches. Ask why a step exists and Arialine answers with the source message.
Every Mermaid diagram type: flowchart, sequence, class, state, ER, C4, architecture, Gantt, mindmap, timeline, user journey, git graph, Sankey, quadrant, XY chart, kanban, block, swimlane, Venn, fishbone and Wardley map. Markdown files become native Slack canvases. Export to PNG, SVG, .mmd and PDF. Works from Slackbot via MCP.
Arialine vs Miro: Miro is a whiteboard priced per member, and editing boards from Slack needs Slackbot on Business+ or Enterprise. Arialine is one flat price per workspace and works on every Slack plan. Arialine vs Mermaid Preview: Mermaid Preview posts a PNG; Arialine adds interactive HTML, saved source, thread edits, versions, AI and exports. Arialine vs Lucidchart, draw.io and Mermaid Live Editor: those live in another tab and end up as stale screenshots in Slack; Arialine keeps diagram, source and history in Slack.
Use cases: system design and architecture reviews, API sequence flows, ER models, incident postmortems, runbooks, onboarding, roadmaps, customer journeys and process documentation. Free plan with every feature; Team is one flat price per workspace, not per seat.