Mermaid Sequence Diagram Example
Sequence diagrams are essential for documenting how components interact over time. Whether you're building API documentation, mapping an authentication flow, or designing microservice communication, Mermaid sequence diagrams make it effortless to communicate complex interactions.
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Open Marmady Editor →Example: API Authentication Flow
This sequence diagram models a standard token-based authentication flow between a browser client, an API server, and a database:
sequenceDiagram
participant Client
participant API
participant DB
Client->>API: POST /login (credentials)
API->>DB: Query user by email
DB-->>API: Return user record
API->>API: Validate password hash
API->>API: Generate JWT token
API-->>Client: 200 OK + JWT
Example: Microservice Request Chain
This example shows how an API gateway routes a request through multiple internal services:
sequenceDiagram
participant Gateway
participant AuthService
participant UserService
participant DB
Gateway->>AuthService: Validate token
AuthService-->>Gateway: Token valid
Gateway->>UserService: GET /user/:id
UserService->>DB: Fetch user data
DB-->>UserService: User record
UserService-->>Gateway: User JSON
Gateway-->>Client: 200 Response
Sequence Diagram Syntax Reference
->>— Solid arrow (synchronous call)-->>— Dashed arrow (response / async)participant Name— Declare a participant explicitlyNote over A,B: text— Annotate interactionloop ... end— Repeat blockalt ... else ... end— Conditional block
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