API testing services: automated checks on the endpoints your product depends on

API testing services check that your endpoints return the right data, reject the wrong requests and hold up under load, without going through the user interface. AutomationDataCamp designs and automates API tests in your repository and your CI/CD pipeline, 100% remotely, in English or French.

What are API testing services?

API testing services are the design, automation and maintenance of tests that call your application programming interfaces directly, over HTTP, and check the responses. Instead of clicking through screens, each test sends a request (create an order, refresh a token, upload a document) and verifies the status code, the response body, the headers and the side effects in the system. Because they skip the browser, API tests run in seconds and break far less often than end-to-end UI tests, which makes them a good place to put most of your functional coverage.

What does API testing cover?

• Functional testing: each endpoint does what the specification says, for valid inputs and for the business rules that matter (totals, statuses, permissions per role).
• Contract and schema testing: responses match the agreed contract, for example an OpenAPI description, so a renamed field or a changed type is caught before a client app or a partner breaks.
• Negative testing: missing fields, wrong types, oversized payloads, duplicate requests and invalid states return clear errors instead of a 500 or corrupted data.
• Authentication and authorization: expired or forged tokens are refused, and one user or tenant cannot read or change another one's data.
• Performance: response times and error rates under a realistic load, on the endpoints your users hit most.
• Integration flows: chained calls that reproduce a real journey, such as sign-up, payment and confirmation, with the data checked at each step.

To compare the main tools, read our article on API testing with Selenium, REST Assured and Postman.

What is included in our API testing service?

• A review of your API description, your critical endpoints and the risks attached to them.
• A test strategy that decides what is tested at API level and what still needs an end-to-end test.
• An automated API test suite, with test data management and readable reports.
• Integration into your CI/CD pipeline, so the suite runs on every merge request (see how to automate tests in CI/CD).
• Skills transfer, so your developers can add and fix tests without us.

Code, tests and documentation are delivered in your repository. You own them from day one.

Which tools are used for API testing?

Common choices include Postman for exploration and shared collections, REST Assured for Java teams, and the request API built into Playwright for teams that want API and browser tests in one codebase. When we build a framework as part of QA industrialisation, API tests live in the same Playwright or Cypress project as your end-to-end journeys, so they share fixtures, configuration and one pipeline. If your team already has a tool it is happy with, the audit says whether to keep it.

How does an API testing engagement work?

1. Scoping call (30 minutes): your APIs, your release pain points, your stack.
2. QA audit: 5 working days to map risks and coverage, define the target strategy and cost the plan. One critical flow is automated as proof of feasibility.
3. QA industrialisation: framework architecture, automation of priority APIs and end-to-end journeys, CI/CD integration and skills transfer. A first phase usually takes around fifteen days.
4. Ongoing testing, if you need it: an embedded tester maintains the suite and tests new endpoints inside your sprints.

How much do API testing services cost?

The QA audit costs €1,000 excl. VAT, fixed price, delivered in 5 working days. QA industrialisation, which covers API test automation and CI/CD integration, starts at €4,500 excl. VAT fixed price; scope, timeline and final price are set after the audit. For ongoing work, embedded QA is billed at €300 excl. VAT per day, with the number of days per week adjusted to your needs.

Who does the work?

The AutomationDataCamp team, led by Oussama Belakhdar, QA architect and founder. Engagements are 100% remote, in English or French, for companies in the US, the UK, Canada, Australia, Europe, the Gulf states and the Nordics. We have tested software in healthcare, finance, e-invoicing, blockchain, logistics, e-commerce and document management.

Two engagements show the kind of results possible: a regression campaign cut from 10 days to 2 hours and a PDF specification turned into a first Playwright test base in one day instead of three weeks. Results depend on context.

Frequently asked questions

What is the difference between API testing and UI testing?

API tests call your endpoints directly and check the responses, without a browser. They are faster and more stable than UI tests, so they usually carry most of the functional coverage, while a smaller set of end-to-end tests checks the journeys users actually click through.

Do you test REST and GraphQL APIs?

We test HTTP APIs, whatever style they use. The audit looks at your API description and your critical endpoints first, then the strategy says how each one should be tested.

Do you need an OpenAPI specification to start?

No. A specification makes contract testing easier, but tests can also be built from your documentation, your existing calls and interviews with your developers.

How much does API test automation cost?

QA industrialisation, which includes API test automation and CI/CD integration, starts at €4,500 excl. VAT fixed price, after a €1,000 QA audit. Ongoing testing is billed at €300 excl. VAT per day.

Who owns the API tests?

You do. Code, tests and documentation are delivered in your repository and run in your pipeline.