API Tester

About WTSS

We are an innovative FinTech that helps banks deliver the best possible digital banking and payment services. We specialise in production verification testing and monitoring. WTSS is the most unusual company in our niche. We can see what the banks themselves cannot. With more bank accounts than any other company, and with Lego structures as an integral part of our offering, we are a small team making a big impact on the largest banks in the world. No two days are the same at WTSS. This dynamic environment is what makes it such a fun and exciting place to work.

Your role

As an API Quality Assurance Tester at WTSS, your responsibilities will include testing our client's Application Programming Interfaces (APIs) from the perspective of the API consumer. This will ensure that they function correctly, securely, and meet performance and quality standards. You will also be responsible for ensuring that this communication works as intended.

You will design, implement, and manage both manual and automated verification journeys for the API channels of banks. You will analyse API documentation, gather test requirements, develop them on our automation platform, develop dashboards and reports, monitor performance and provide support to our customers when required.You will participate in calls as our API test expert alongside the Service Delivery Manager.With your experience in testing, knowledge of automation and drive for quality, you will be able to tackle complex challenges and use your resourcefulness to find innovative solutions that help clients get the insights they are looking for.

Key responsibilities

• Analyse API specifications and assess work

  • Study API documentation to understand functionality, expected inputs/outputs, and constraints.

  • Assess the work that needs to be done to develop the API connectivity between the bank and our Diagnostics Platform.

  • Develop test plans, cases, and scenarios based on API requirements and use cases in collaboration with the client.

  • Assess ythe work that needs to be done to create automation scripts and/or execute tests manually

• Develop API Connectivity and automate tests

  • Develop the API connectivity between the bank and our Diagnostics Platform.

  • Script automated tests

• API Functional Testing

  • Verify if the API functions as expected by testing endpoints, request/response formats, and workflows.

  • Check input validation, error handling, and business logic.

  • Check outputs or results to verify a bank’s downstream processes

• Performance Testing

  • Measure the API’s responsiveness under different loads to ensure it meets performance benchmarks.

  • Identify bottlenecks or scalability issues.

• Security Testing:

  • Ensure the API is secure against common vulnerabilities like unauthorized access, SQL injection, and data leaks.

• Usability testing

  • Record defects or standouts in the developer experience

  • Evaluate processes like onboarding, environment promotion, support

• Defect Reporting

  • Identify and report issues such as incorrect responses, latency, or unexpected behavior.

• Maintain and Support automated API production verification tests

For this full-time, on-site role we are looking for an analytical, detail-focussed and communicative developer or API tester, who has excellent C# programming skills, extensive experience in API connectivity and demonstrable experience in testing. Preferably you have experience with open banking or other direct bank channels. You enjoy teamwork, bring something unique to the table and are a fun person to work with.

• Minimum of 2 years of experience in API testing

• Proficiency in tools such as Postman, SoapUI, Swagger and cURL

• Strong understanding of SOAP and RESTful APIs and web services

• Ability to write clear, concise, and comprehensive test plans and test cases

• Knowledge of software QA methodologies, tools, and processes

• Excellent analytical and problem-solving skills

• Strong attention to detail and ability to work independently

• Good communication skills and ability to collaborate with cross-functional teams

• You are permitted to work in The Netherlands. Please note that WTSS does not support relocation or VISA applications.

If you are ready to take the next step in your career and be part of a team driven by fun, wisdom and innovation, we look forward to hearing from you! To apply please click the button and follow the process. Let us know why you are the perfect candidate for this role and how your experience and skills match what we are looking for.