Design, QA & Growth
APIs Tested Beyond the UI
Direct testing of REST, GraphQL and SOAP APIs for correctness, error handling, contracts and load, long before a user interface exists.
Overview
API Testing
API testing checks the layer where your systems actually exchange data. Testing below the interface is faster and more precise: we send requests directly, verify status codes, response bodies, headers and side effects, and probe how the API behaves with missing fields, wrong types, expired tokens and unexpected sequences. This often exposes problems that user interface testing alone would never reveal.
We build automated API suites that run in your pipeline and, where several services depend on one another, contract tests that catch breaking changes before consumers do. We also check authentication flows, pagination, idempotency and rate limits, and can run focused load checks to see how endpoints behave under pressure.
Context
Problems we solve
- 01
Breaking changes
A small API change can break mobile apps and partners. We use contract tests to catch these early.
- 02
Weak error handling
APIs often fail badly on bad input. We test invalid, missing and oversized payloads deliberately.
- 03
Auth and permission gaps
Endpoints may expose data to the wrong caller. We test tokens, scopes and object-level access.
- 04
Undocumented behavior
Specs drift from reality. We validate responses against OpenAPI definitions and flag mismatches.
Capabilities
What we deliver
- 01
Functional API testing
We verify endpoints return correct data, codes and side effects for valid and invalid requests.
- 02
Automated API suites
We build suites in tools like Postman or code frameworks and run them in CI.
- 03
Contract testing
We verify provider and consumer agreements so integrations do not break silently.
- 04
Auth and access checks
We test authentication flows, role scopes and access to other users' records.
- 05
Performance sampling
We run targeted load tests on key endpoints to check response times and limits.
- 06
Schema validation
We compare live responses to OpenAPI or JSON schema definitions to catch drift.
Where it fits
- Testing a backend before the front end exists
- Verifying third-party integrations
- Contract checks between microservices
- Regression suites for a public API
- Load checks on critical endpoints
Technologies we use
- Postman
- REST Assured
- Newman
- Pact
- k6
- JMeter
- OpenAPI
- GraphQL
Approach
How we deliver
- 1
Discover
We learn your goals, users, constraints and existing systems before proposing anything.
- 2
Plan
Scope, priorities, architecture and milestones are agreed so everyone knows what ships when.
- 3
Design
User flows, interfaces and technical design are shaped and reviewed with you early.
- 4
Build
Work is delivered in short iterations with regular demos, so progress is always visible.
- 5
Test
Functional, integration and performance checks run throughout, not only at the end.
- 6
Launch & support
We deploy, monitor and keep improving the product after it goes live.
FAQs
Common questions
Have a question that is not covered here? Get in touch.
Why test APIs separately from the user interface?
API tests run faster, break less often and pinpoint problems more precisely. They also cover behavior that mobile apps, partners and other services rely on, which UI tests may never touch.
Can you test APIs we do not own?
Yes, for third-party services we depend on, as long as their terms allow it and we use sandbox environments. This helps detect changes that would affect your integration.
Does API testing include security?
We check basic authentication and authorization behavior as part of functional testing. Deeper vulnerability assessment is a separate activity, which we cover under security testing.
Explore
Keep exploring
Let's build what's next
Tell us about your idea, product or legacy system. Send us a message and we will help you scope the right next step.