OpenAPI Contract Checklist

Paths, operations, parameters, request bodies, responses, schemas, examples and security review. Last updated August 31, 2026.

OpenAPI descriptions are most useful when they are treated as working contracts, not decorative documentation. The OpenAPI Specification defines the root document, paths, operations, parameters, request bodies, responses and reusable components at spec.openapis.org/oas/latest.html. The learning guide explains that API endpoints are represented as paths and operations at learn.openapis.org/specification/paths.html. This checklist helps teams review the contract before client code, tests and docs drift apart.

Minimum contract shape

openapi: 3.1.0
info:
  title: Example API
  version: 1.0.0
servers:
  - url: https://api.example.com
paths:
  /customers/{customerId}:
    get:
      summary: Get a customer
      parameters:
        - name: customerId
          in: path
          required: true
          schema:
            type: string
      responses:
        "200":
          description: Customer found
        "404":
          description: Customer not found

Review paths before schemas

Area	Question	Why it matters
Servers	Does the server URL match the real environment?	Generated clients and docs will call the wrong host if this drifts.
Paths	Do path names start with `/` and match production routes?	Small route mismatches create expensive client debugging.
Operations	Is each method described with a clear summary and response set?	Consumers need expected outcomes, not just endpoint names.
Parameters	Are path parameters required and typed?	Path variables must be explicit for reliable validation and generation.
Responses	Are success and common error responses documented?	Client handling depends on 400, 401, 403, 404, 409, 422 and 429 behavior.

Payload and schema checks

Keep request bodies separate from path and query parameters.
Document nullable values deliberately instead of copying one accidental sample.
Use examples that match the declared schema, including arrays and nested objects.
Name reusable schemas in components.schemas when multiple endpoints share the same shape.
Review enum values, date formats and IDs with product or backend owners before publishing.

Security and auth review

components:
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT
security:
  - bearerAuth: []

Security declarations should match real behavior. If one operation is public, override it explicitly. If an endpoint requires a scope, role or tenant boundary, write that in the operation description and test it in the API checklist.

Pre-release checklist

contract version:
server URLs checked:
paths match deployed routes:
operation IDs unique:
path params required:
query params typed:
request body schema reviewed:
success responses documented:
error responses documented:
auth scheme matches production:
examples validate:
breaking change noted:

A useful OpenAPI file lets another developer build, test and debug against the API without asking what the route, body, status code or auth rule means.