Turn a text script of who-calls-who into a live UML sequence diagram — actors, arrows, and responses — exportable as SVG or PNG.
A sequence diagram maps out who calls whom, and in what order — the standard way to document an API request flow, an auth handshake, or a chain of service calls before or during a design review. This tool takes Mermaid's sequenceDiagram syntax and renders it live, so the diagram in your PR description or design doc matches the text you can also keep in version control.
A solid line (->>) is a synchronous call/request, a dashed line (-->>) is a response or async return, and a plain -> draws the arrow without the solid arrowhead. Mixing solid calls with dashed responses is what makes a request/response flow readable at a glance.
Yes — Mermaid's sequence diagram syntax supports activate/deactivate for lifelines, plus loop, alt, and opt blocks for repeated or conditional steps, all recognized by this tool since it uses the same rendering engine as full Mermaid.
No — sequencediagram.org uses its own syntax, while this tool uses Mermaid's sequenceDiagram syntax, which is the more widely-supported flavor (the same one rendered natively by GitHub, GitLab, and Notion) if you want the diagram source to keep working wherever else you paste it.
No — rendering happens entirely in your browser; nothing you type is transmitted anywhere.
Click Copy share link and send the URL. The diagram text is compressed into the part of the URL after the #, which browsers never send to a server, so the diagram stays private and nothing is stored on our side. Opening the link reproduces the diagram exactly.
Yes — your latest diagram is autosaved in this browser and restored next time. It never leaves your device. A share link always opens the shared diagram instead of your saved one.
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