API Testing Services

The problem

The UI can look fine while the API writes the wrong field, returns 200 with an error body, or accepts a token it should reject. If the only API test is “the page loaded,” you will meet the defect in a mobile client, a partner integration, or a report — not in the happy-path click.

API testing services validate the contract itself.

What’s at risk without it

• Frontend and backend disagreeing on a field name, type, or null
• Auth holes: missing token accepted, or a token from role A used as role B
• Error paths that return 500 with no usable body, or 200 with a silent failure
• Breaking a consumer when you “only changed the backend”
• Third-party APIs changing shape and nobody noticing until production

What we test

• REST/HTTP request and response shape, status codes, and headers you care about
• Auth: missing, expired, wrong role, replayed token (as QA — not a full security engagement)
• Validation and boundary values on the API, not only in the form
• Idempotency and retries where the product claims them
• Error and timeout behaviour
• Integration points between your API and a named third party, when we have a sandbox

We do not pretend GraphQL, gRPC, or event streams are covered unless they are in the plan. Name the surface.

Parent hub: web, mobile, API, and database. Data written through the API is checked on database testing when you want that layer too.

Our approach

1. Collect the contract: OpenAPI, examples, or a working collection
2. Build cases for success, validation failure, auth failure, and a few destructive paths in a safe environment
3. Run them against a named base URL and build
4. Log request, response, and expected contract — not “API is broken”
5. Re-run after the backend changes, even if the UI did not

Collections we have used include Postman and similar HTTP tools. Named page: Postman API testing. That is not a partnership claim.

Deliverables

• Case set mapped to endpoints or operations
• Failures with request/response evidence (secrets redacted)
• A short list of contract gaps (undocumented fields, lying status codes)

Suitable for

API-first products, mobile backends, and teams who integrate with partners — especially before a version bump.

FAQs

Can you test the API without the frontend?

Yes. That is the point.

Do you need a staging environment?

Yes. We do not run destructive cases against production unless you explicitly scope a read-only check.

Is this the same as test automation?

The cases can be automated. This page is the discipline. Test automation is how you choose to repeat them.