SeamaidStart free

Live sequence diagrams

Diagram the conversations between services.

Write Mermaid, inspect the flow, and edit the diagram where the conversation breaks down. Source, chart, and version history stay in one workspace.

Start freeSee the workflow

Browser based · Mermaid native · Versioned automatically

login-flow.mmd live
Mermaid source
  1. 01sequenceDiagram
  2. 02participant User
  3. 03participant Browser
  4. 04participant API
  5. 05participant DB
  6. 06User->>Browser: Enter details
  7. 07Browser->>API: POST /login
  8. 08API->>DB: lookup user
  9. 09DB-->>API: user record
  10. 10API-->>Browser: 200 OK
rendered flowUserBrowserAPIDBEnter detailsPOST /loginlookup useruser record200 OKclick → source 07

The chart is the editor

Stay with the flow. The source comes to you.

A sequence diagram is where service behavior becomes legible. Seamaid makes every rendered element a route back to the line that produced it—then lets you fix the words without leaving the chart.

Click to source

Select a message in the chart and the matching Mermaid line moves into view.

Edit in place

Change actors, messages, and notes directly on the rendered conversation.

Keep the trail

Automatic snapshots preserve the path from the first sketch to the current flow.

One continuous workflow

From syntax to shared understanding.

No export-and-correct loop. The source and its meaning stay connected from the first line onward.

01 / 03

Write the source

Start with Mermaid you already know. The chart redraws as the conversation changes.

02 / 03

Follow the flow

Click any actor, message, or note to land on the exact source line behind it.

03 / 03

Correct it in place

Double-click diagram text, make the change where you found it, and retain the version.

Model Context Protocol

Give your AI tools the same chart.

Compatible agents can list, read, create, update, rename, and delete charts through Seamaid’s MCP server. You keep the visual context; the agent works with the source.

stdiostreamable HTTPsame chart store
agent session
01list_charts
↳ login-flow.mmd
02read_chart
↳ sequenceDiagram …
03update_chart
↳ Chart updated
login-flow.mmdupdated
Browser
API
POST /login
200 OK + token

Ready when the flow is not

Start with the service call you’re debugging.

Start free

Your first chart is already waiting