What API testing services include

What do API testing services include?

API testing services check that each endpoint of an application programming interface (API) accepts the right input, returns the right data and status codes, rejects bad requests clearly, enforces access rules and performs well. Testing happens directly against the API, so problems are found before they reach any screen.

Our API testing work usually includes:

• Reviewing your API documentation, such as an OpenAPI (Swagger) file or GraphQL schema.
• Designing test cases for each endpoint: happy paths, edge cases and error cases.
• Automated test suites that run on every build in your CI/CD pipeline.
• Contract and schema checks between services and consumers.
• Security checks for authentication, authorization and data exposure.
• Load checks on key endpoints, with deeper load tests when needed.
• Clear defect reports with the exact request, response and environment.

API testing vs UI testing

What is the difference between API testing and UI testing?

API testing checks the business logic and data directly through requests and responses. UI testing checks what a person sees and clicks. API tests are faster, more stable and catch bugs earlier, while UI tests confirm the full user journey works. Most teams need both, with far more API tests than UI tests.

Because one API often serves your web app, mobile app and partners, a single API bug can affect every channel at once. That is why our test automation services put most automated coverage at the API layer.

Types of API tests we run

What types of API tests do you run?

We combine several kinds of API tests, because each finds a different class of problem. The mix depends on how critical the API is and who consumes it.

Here are a few illustrative test cases for an orders API, to show the level of detail we work at:

REST, GraphQL and SOAP testing

How does testing differ for REST, GraphQL and SOAP APIs?

The goals are the same, but each API style has its own risks. REST API testing needs checks on each endpoint and HTTP method. GraphQL APIs need checks on queries, mutations and how deep or expensive a query can get. SOAP APIs need strict XML and WSDL contract checks.

Contract testing

What is API contract testing, and why does it matter?

Contract testing checks that an API and the apps that use it agree on the request and response format. It catches breaking changes, such as a renamed field or a new required parameter, before they are deployed. This matters most when several teams or partners depend on the same API.

We use two approaches:

• Schema validation: every response is checked against your OpenAPI or GraphQL schema, so undocumented changes fail the build.
• Consumer-driven contracts: with tools such as Pact, each consuming app records what it needs, and the API is tested against those expectations before release.

API security testing

How do you test API security?

We test API security against the OWASP API Security Top 10, which lists the most common and damaging API risks. The most frequent problems we look for are broken authorization, weak authentication and APIs that return more data than the user should see.

• Object-level authorization: can user A read or change user B’s records by changing an ID?
• Authentication: are tokens validated, do they expire, and are login endpoints protected from guessing?
• Property-level exposure: do responses include sensitive fields the screen never shows, and can users set fields they shouldn’t?
• Function-level authorization: can a normal user call admin endpoints?
• Resource limits: are there rate limits, page size limits and query cost limits?

These checks fit inside regular QA. A full penetration test by a specialist security firm is a separate service, and we can help you prepare for one.

Third-party integrations and mocking

How do you test third-party integrations?

Our integration testing services work in two layers. First, we check your code against realistic mocks of the third-party API, so we can simulate slow responses, errors and unusual data on demand. Then we run a smaller set of tests against the provider’s sandbox to confirm the real connection works.

Mocks are useful because many third-party problems can’t be triggered on purpose in a sandbox, such as a payment provider timing out halfway through a charge. We check that your system retries safely, doesn’t create duplicates and shows users a helpful message.

Tools and CI/CD

Which API testing tools do you use?

We choose tools that fit your stack and that your developers can maintain. Common choices include:

• Postman and Newman for collections that run both manually and in CI.
• REST Assured for Java teams, and Playwright or SuperTest for JavaScript and TypeScript teams.
• Pact for consumer-driven contract tests.
• WireMock or Prism for mocking dependencies.
• k6 or JMeter for load on key endpoints, covered in more depth by our performance testing services.

Suites run in GitHub Actions, GitLab CI, Jenkins or Azure DevOps on every pull request, with results and failed requests visible to your developers.

Healthcare and FHIR APIs

Do you test healthcare APIs such as HL7 FHIR?

Yes. Many clinic, billing and patient apps exchange data through HL7 FHIR APIs or connect to EHR and practice management systems. We test resource formats, required fields, search parameters, error handling and access rules for these integrations.

CloudOryx is not HIPAA certified. For healthcare APIs we agree data rules with you in writing, work only in environments you control, and test with synthetic or masked data, never real patient records.

How we start

How does an API testing engagement start?

As an API testing services company, we start small and expand once the first suite proves its value.

1. Review: read your API docs, map endpoints by business risk and agree priorities.
2. Design: write test cases for the highest-risk endpoints, including security and error cases.
3. Automate: build the suite in your repository and connect it to your pipeline.
4. Report: log defects with full request and response details in your tracker.
5. Expand: add contract tests, integration mocks and load checks sprint by sprint.

API testing works well alongside our outsourced QA testing services and mobile app testing, since most app bugs trace back to the API. See our full range on the QA as a Service page.