Focus on one endpoint at a time and verify what it accepts, returns, and rejects. Confirm request method, path, headers, query parameters, and body shape before asserting status codes and response fields. For each call, compare the returned payload against the expected schema, required properties, and error conditions.
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Endpoint Validation Areas
GET requests
Verify query parameter handling, filter values, and pagination inputs. Confirm the response returns the correct collection or record, with matching status codes and expected body structure.
POST requests
Check required fields, content type, and validation errors for missing or invalid data. Assert that created resources return the correct status and response body values.
PUT requests
Validate full or partial updates against the endpoint contract. Confirm updated fields persist, unchanged fields remain stable, and invalid payloads return precise errors.
DELETE requests
Verify deletion responses, idempotent behavior, and follow-up reads when applicable. Confirm the endpoint rejects unauthorized deletes and returns the expected status for missing resources.
Headers and query params
Check required headers such as Content-Type, Accept, and custom version headers. Validate query parameters for type, format, allowed values, and server-side defaults.
Response body structure
Assert field names, nesting, data types, and null handling in the response. Compare the payload to the expected schema so regressions are caught quickly.
Auth and token checks
Test bearer tokens, expired credentials, and missing authorization headers. Confirm protected endpoints return the right status and error message when authentication fails.
Common Testing Questions
What should I validate first on an endpoint?
Start with the request contract: method, path, headers, query parameters, and body fields. Then verify the response status, schema, and any required business rules for that endpoint.
How do I assert response data correctly?
Check exact fields, data types, nested objects, and expected values where they are stable. For dynamic values, assert format and presence instead of fixed content.
How should authentication be tested?
Run the same request with a valid token, an expired token, and no token at all. Confirm each case returns the expected authorization result and error response.
What edge cases matter most?
Focus on missing required fields, invalid parameter values, empty payloads, and malformed headers. Also test resource-not-found cases and duplicate submissions where relevant.