Edit sequence diagram

Edit a time-ordered sequence diagram of participants and messages.

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ToolSequence Diagram Editor
Input
Output
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How it works

Participants and messages are parsed in order, lifelines are created for each participant, and message arrows plus activation blocks become a time-ordered diagram. Control constructs such as alt and loop group subsequent messages without changing their order.

  • Vertical position carries time order while horizontal position identifies participants.

Worked example

API Request
Generate a sequence diagram for an API request flow
Input
											Title: API Call
Participants: [{"name":"Client","type":"participant"},{"name":"Server","type":"participant"},{"name":"Database","type":"participant"}]
Messages: [{"from":"Client","to":"Server","text":"GET /users","type":"solid-arrow"},{"from":"Server","to":"Database","text":"SELECT * FROM users","type":"solid-arrow"},{"from":"Database","to":"Server","text":"Result set","type":"dashed-arrow"},{"from":"Server","to":"Client","text":"200 OK + JSON","type":"dashed-arrow"}]
Autonumber: true
Output
												sequenceDiagram
    title API Call
    autonumber
    participant Client
    participant Server
    participant Database
    Client->>Server: GET /users
    Server->>Database: SELECT * FROM users
    Database-->>Server: Result set
    Server-->>Client: 200 OK + JSON

When to use this

API flows, login handshakes, and distributed-incident reviews edit sequence diagrams.

Edge cases

  • A participant alias must remain consistent across messages.
  • Self-messages need a distinct loopback rendering.
  • Nested alt and loop blocks change grouping without changing event order.

References