Catch Breaking API Changes at PR Time, Not in Production
Consumer-driven contract testing with Pact, OpenAPI schema validation, and integration tests that fail the build before an incompatible change can merge.
You might be experiencing...
API and contract testing catches breaking API changes at pull-request time - before a renamed field or reshaped response can reach production and page your on-call.
Why API Breaks Are Sneaky
UI bugs announce themselves. API breaking changes don’t. There’s no red screen - just a mobile client showing stale data, a webhook that quietly stopped firing, or a partner integration dropping events because a field got renamed. You find out from a support ticket, hours or days later.
The fix is to make the break visible where it happens: at the pull request. That’s exactly what contract testing does.
What We Build
Consumer-driven contract tests with Pact - for every high-blast-radius endpoint, we capture what each consumer actually needs from the response. Change the provider in an incompatible way and the contract test fails the build, before the code merges. No more discovering dependencies in production.
OpenAPI schema validation - we check that your implementation matches your spec. Schema drift between docs and reality is one of the most common integration bugs, and it erodes every integrator’s trust in your API. If your specs are missing or stale, we generate accurate ones from real traffic and keep them enforced.
Integration tests - for the flows that matter most, we exercise real calls: request and response shapes, error codes, and authentication. This confirms the wiring works, not just that the shapes agree.
Where It Stops - On Purpose
This service is about correctness, not capacity. We do not fold load testing in here, because doing both half-well serves neither. When the real question is how your API holds up under traffic, we hand off to dedicated specialists at loadtest.qa and performance.qa. Contract tests catch the wrong shape; load tests catch the wrong capacity - different jobs, different tools.
How It Connects
Contract tests need somewhere reliable to run. If your pipeline is slow or flaky, our CI/CD test infrastructure work makes the gate fast enough that people actually wait for it.
The Outcome
Your services stop breaking each other silently. Breaking changes fail the build, your OpenAPI docs stay honest, and frontend and backend stop guessing at API shapes.
Engagement Phases
API Surface & Consumer Mapping
We map your API surface and, crucially, who consumes each endpoint - other services, the web app, mobile clients, third-party integrators. Each endpoint is scored by blast radius and change frequency so we test the contracts that actually hurt when they break.
Contract Tests & Schema Validation
We build consumer-driven contract tests with Pact and validate implementations against your OpenAPI schemas. Where specs are missing or stale, we generate them from real traffic. Integration tests cover the request/response shapes, error codes, and auth flows that matter most.
PR-Time Gating & Handoff
We wire contract and schema checks into your pipeline so an incompatible change fails the build before merge, not in production. Then we document the workflow and hand it to your team so adding a new contract test becomes routine.
Deliverables
Before & After
| Metric | Before | After |
|---|---|---|
| Breaking Changes | Discovered in production via support tickets and rollbacks | Caught at PR time - the build fails before merge |
| Spec Accuracy | OpenAPI docs drifted from the real API months ago | Schema validation keeps docs and implementation in sync |
| Team Coordination | Frontend and backend block each other on unknown API shapes | Contracts make the agreed shape explicit and enforced |
Tools We Use
Frequently Asked Questions
What's the difference between contract testing and integration testing?
Contract testing verifies that a provider and its consumers agree on the shape of the API - request and response schemas, error codes, auth - and it does this without spinning up every service together. Integration testing exercises real calls between components. We use both: contracts catch shape mismatches fast and cheaply at PR time, integration tests confirm the wiring actually works end to end.
How much does API & Contract Testing cost?
Book a free call to discuss scope and get a custom quote.
We don't have OpenAPI specs - can you still help?
Yes. We generate specs from real API traffic, Postman collections, or your code, and they become a deliverable you keep. From there we add schema validation so the spec and the implementation stay in sync going forward.
Do you cover load and performance testing too?
That's deliberately not part of this service - contract and integration testing is about correctness, not capacity. When you need to know how your API behaves under real traffic, we hand off to dedicated load testing partners like loadtest.qa and performance.qa, who do that properly. Mixing the two rarely serves either well.
Test automation, engineered.
Book a free 30-minute call. We assess your test automation gaps and show you how a modern SDET practice ships faster with fewer escapes.
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