Senior Quality Assurance Engineer (Backend)

BUX B.V.; Amsterdam; On-site; EUR 70,000 - 110,000; Full time

Job summary

BUX is seeking a Senior Quality Assurance Engineer (Backend) in Amsterdam to own quality across our backend services. You’ll design, implement, and maintain automated tests for REST APIs, while executing manual testing where needed and maturing QA processes within the squad.

You will collaborate with Product, Dev, and DevOps, ensuring data integrity and regulatory compliance in a fast-paced fintech environment.

Qualifications

• 5–7+ years of software quality assurance in fintech.
• Strong hands-on manual and exploratory testing with test automation.
• Proficiency in API testing (REST) and microservices architectures.
• Hands-on experience with test automation frameworks such as Selenium and Playwright with TypeScript.
• Proficiency in at least one programming language (Java/Kotlin)
• Understanding of CI/CD pipelines and integration of automated tests (GitHub Actions)
• Practical experience with Postman/Newman, Charles Proxy, and Xray (or similar test management tooling)
• Comfortable validating data across multiple database technologies and asynchronous event flows
• Experience helping establish or mature QA processes within a squad or team
• Experience working in a fast-paced Agile environment
• Excellent communication and collaboration skills with cross-functional teams
• This role reports to the Staff QA Engineer

Responsibilities

• Design, implement, and maintain automated tests for backend REST services
• Execute manual and exploratory testing where automation isn't feasible
• Help build and mature QA processes, standards, and definition of done within the squad
• Apply quality gates and acceptance criteria in close collaboration with Product and Development teams
• Participate in design reviews for owned backend features to provide a QA perspective early in the development cycle
• Monitor and track key quality metrics, test coverage, and defect trends for backend services
• Perform bug triage, reproduction, and prioritisation with development teams
• Integrate automated regression, smoke, and integration test suites into CI/CD pipelines (GitHub Actions)
• Support test environment setup, data provisioning, and maintenance in coordination with DevOps
• Use approved GenAI tooling with sanitised data to accelerate test design and automation, subject to human review, security policies, and validation of generated tests

Skills

Manual testing

Automation testing

API testing (REST)

Fintech domain

Java/Kotlin

CI/CD

GitHub Actions

Selenium

Playwright

TypeScript

Communication

Tools

Selenium

Playwright

Postman/Newman

Charles Proxy

Xray

Job description

We are looking for a Senior Quality Assurance Engineer (Backend) to join our BUX team based in Amsterdam.

Our engineering team sits at the heart of the company. We have a well-rounded team that cares about building great products that matter. You'll be part of a modern fintech company where you can try things, break things, fix them, and learn fast. Your work is visible, your input matters, and you help shape both the product and how we build it. We stay close to what's happening in the world of investing and fintech, and we share what we learn. It's a place where you can stretch your skills, contribute to something real, and grow alongside people who take their craft seriously and enjoy building things together.

What you will do

In a fintech environment, quality is not just about catching bugs; it's about ensuring financial accuracy, maintaining regulatory compliance, and safeguarding our users' trust. You'll play an active hands-on role in upholding quality across the backend services that power our platform.

As a Senior Quality Assurance Engineer for our App Backend team, your job is to get things done. This could mean:

• Design, develop, and maintain automated tests (integration, end-to-end, regression) for backend REST services
• Execute manual and exploratory testing where automation is not feasible
• Help build and mature QA processes, standards, and definition of done within the squad
• Apply quality gates and acceptance criteria in close collaboration with Product and Development teams
• Participate in design reviews for owned backend features to provide a QA perspective early in the development cycle
• Monitor and track key quality metrics, test coverage, and defect trends for backend services
• Perform bug triage, reproduction, and prioritisation with development teams
• Integrate automated regression, smoke, and integration test suites into CI/CD pipelines (GitHub Actions)
• Support test environment setup, data provisioning, and maintenance in coordination with DevOps
• Use approved GenAI tooling with sanitised data to accelerate test design and automation, subject to human review, security policies, and validation of generated tests

Our tech stack

Java, Kotlin, Spring Boot, GCP, Kubernetes, GitHub Actions, REST APIs, Selenium, Playwright/TypeScript, Postman/Newman, Charles Proxy, Xray, CloudSQL, PostgreSQL

What you need to succeed

We are looking for you if you are passionate about quality, you have strong hands-on testing skills, and you thrive in a fast-paced fintech environment. Furthermore, we require:

• 5–7+ years of experience in software quality assurance, with a senior-level track record of hands-on testing in the fintech domain
• Strong hands-on manual and exploratory testing skills alongside solid test automation experience
• Strong knowledge of API testing (REST) and microservices/event-driven architectures
• Hands-on experience with test automation frameworks such as Selenium and Playwright with TypeScript
• Proficiency in at least one programming language (Java/Kotlin)
• Understanding of CI/CD pipelines and integration of automated tests (GitHub Actions)
• Practical experience with Postman/Newman, Charles Proxy, and Xray (or similar test management tooling)
• Comfortable validating data consistency across multiple database technologies and asynchronous event flows
• Experience helping establish or mature QA processes within a squad or team
• Experience working in a fast-paced Agile environment
• Excellent communication and collaboration skills with cross-functional teams
• This role reports to the Staff QA Engineer

Nice-to-haves

• Experience with fintech or financial services testing (financial accuracy, transactional data, regulatory compliance)
• Experience with performance and security testing
• Knowledge of financial regulations and compliance standards (KYC/AML)
• Familiarity with event-driven and event sourcing architectures

Why join BUX as a Senior QA Engineer?

• You will have a real impact on quality for a high-growth fintech company that serves thousands of users
• You will work with modern backend technologies and have the freedom to introduce better testing practices
• You'll collaborate with experienced, passionate engineers who value quality and continuous improvement
• You'll be part of a company that values your ideas and encourages innovation at every level
• You will help build products that democratize investing and make a real difference in people's financial lives

How we hire

To learn more about our approach to hiring and how to prepare for your interviews, check out our How we hire section.

Adjustments for the hiring process

We want you to feel empowered to show your best self during the application process. If there's anything we can do to accommodate you better (interview timing, place, etc), please let us know in your application form.

Benefits

Read morehereabout the benefits and perks you receive when you join BUX.

BUX for everyone

At BUX, we’re committed to making investing accessible and affordable for everyone through our intuitive app. We believe that a diverse team with a range of backgrounds, skills, and perspectives is key to achieving this mission. By embracing diversity, we strengthen our ability to innovate and serve our customers better.

To fully benefit from our diversity, it’s essential that everyone feels safe, included, and valued. We are dedicated to creating a workplace where each of us can bring our full selves to work and contribute to our shared goals.