Senior QA Engineer - Kafka/Event Streaming

BUX B.V.; Amsterdam; On-site; EUR 75,000 - 110,000; Full time

Job summary

BUX B.V. in Amsterdam is seeking a Senior Quality Assurance Engineer (Event Streaming) to validate the correctness, reliability, and resilience of our Kafka-based systems.

You will own test design, automation, and governance for the Backend Broker team in a fast-paced fintech environment. The role requires hands-on testing with Kafka, REST APIs, and event-driven architectures, plus strong automation with Selenium/Playwright and TypeScript.

Qualifications

• 5–7+ years of experience in software quality assurance, with a senior-level track record in fintech
• Hands-on testing experience with Kafka or comparable event-streaming platforms
• 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 for event-driven systems
• 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, develop, and maintain automated and manual tests for Kafka-based producers, consumers, and event flows
• Execute manual and exploratory testing where automation is not feasible
• Integrate automated regression, smoke, and integration test suites into CI/CD pipelines (GitHub Actions)
• Help build and mature QA processes and standards for event-driven systems within the squad
• Apply quality gates and acceptance criteria in close collaboration with Product and Development teams
• Participate in design reviews for owned features and event schemas to provide a QA perspective early in the development cycle
• Monitor and track key quality metrics, test coverage, and defect trends for the streaming domain
• Validate message ordering, delivery guarantees, idempotency, and exactly-once/at-least-once semantics
• Validate producer and consumer contracts and schema compatibility as services evolve
• Perform failure-mode and resilience testing — broker failures, consumer lag, retries, dead-letter handling, and replay scenarios
• Perform bug triage, reproduction, and prioritization with development teams
• Support test environment setup, data provisioning, and maintenance in coordination with DevOps
• Use approved GenAI tooling with sanitized data to accelerate test design and automation, subject to human review, security policies, and validation of generated tests

Skills

Java

Kotlin

API testing

QA processes

Agile

Test automation

Tools

Kafka

GitHub Actions

Postman

Newman

Charles Proxy

Xray

Selenium

Playwright

Job description

BUX B.V. in Amsterdam is seeking a Senior Quality Assurance Engineer (Event Streaming) to validate the correctness, reliability, and resilience of our Kafka-based systems.

You will own test design, automation, and governance for the Backend Broker team in a fast-paced fintech environment. The role requires hands-on testing with Kafka, REST APIs, and event-driven architectures, plus strong automation with Selenium/Playwright and TypeScript.