Workflow guide
API debugging to sequence diagram
Turn OpenAPI paths, Postman collections, HAR traffic, and error notes into sequence diagrams for backend review.
Start from the contract
Use a focused OpenAPI path group so the diagram explains one workflow instead of the entire API.
Compare request order
Preview Postman or HAR traffic to see whether runtime calls match the documented sequence.
Document the failure path
Add error responses, retries, and timeout behavior so incident notes explain what actually happened.
Paste-ready example
Checkout OpenAPI path
Start from a narrow OpenAPI path group so the sequence diagram explains one request path and its failure response.
Open this exampleopenapi: 3.0.0
paths:
/checkout:
post:
summary: Create checkout session
responses:
"201":
description: Checkout created
"402":
description: Payment required
/checkout/{id}:
get:
summary: Read checkout status
responses:
"200":
description: Checkout statusWorkflow FAQ
Why use a sequence diagram for API debugging?
A sequence diagram makes request order, actors, retries, and failure responses visible, which is often faster than reading logs line by line.
Should the diagram include every endpoint?
No. Use one user journey, incident, or API path group per diagram so reviewers can see cause and effect clearly.
Related tools
OpenAPI to Sequence Diagram
Convert OpenAPI paths into a Mermaid sequence diagram locally.
Postman Collection からシーケンス図
Postman Collection からシーケンス図: Convert Postman collection JSON into a readable API request sequence diagram.
HAR ファイルからシーケンス図
HAR ファイルからシーケンス図: Turn browser Network HAR exports into request sequence diagrams for debugging and documentation.
API エラーフロー図
API エラーフロー図: Turn API status codes, failure conditions, and recovery actions into an error flow diagram.