Responsibilities

We are seeking a Senior QA Engineer to join our Card Processing team

You will design and build the quality systems that keep our payment platform reliable at scale - in an environment where new code is produced using AI tooling and judgment is the bottleneck, not generation speed

This is not a traditional “write and execute test cases” role

We believe software engineers own their tests — your job is to make them better at it

You will own the sensor strategy that catches what AI gets wrong, verify that test intent matches business requirements, and raise the quality bar for the entire team

Design and implement layered quality sensors across our CI/CD pipeline — from static analysis to AI-driven code review passes

Improve and maintain E2E test suites for critical payment flows (card authorisation, clearing and settlement, tokenisation, 3D Secure)

Review PRs for test intent alignment — ensuring AI-authored and human-authored code meets the same quality bar

Identify test coverage gaps and prioritise them by risk (customer impact, regulatory exposure)

Build load testing and performance validation frameworks

Collaborate with the team on quality strategy — you raise the bar, you don’t gatekeep it

Explore chaos engineering approaches to validate system resilience

Contribute to audit-trail thinking — ensuring generated diffs and suppressed checks are traceable and defensible

Benefits

Ongoing learning and development opportunities

Retirement planning

Charitable donation matching

Volunteer opportunities





Employee development fund

Monthly happy hours

Free haircuts in our salon located at HQ

Complimentary dry cleaning at HQ

Valet parking at HQ

Shuttle service to/from NYC

Gym located at HQ

River Cafe at HQ

Qualifications

Strong proficiency in English — written and verbal

Familiarity with CI/CD pipelines, containerisation, and infrastructure-as-code

Experience testing RESTful APIs and event-driven systems

Strong analytical thinking — you pull bugs back to the spec, not just the code

Excellent communication skills — this role enables and mentors, not just audits; you need to teach, not agitate

5+ years in software engineering with a strong focus on quality and testing (equivalence partitioning, boundary analysis, risk-based prioritization)

Comfort with regulated environments — you think in terms of audit trails, blast radius, and data classification

Demonstrated AI fluency — you use AI assistants daily, you know when they’re wrong, and you know when not to use them

Proficiency in Go (or strong willingness to learn — test-design thinking matters more than language syntax)

Understanding of failure modes in distributed systems (event ordering, retries, idempotency, eventual consistency)

Experience using observability platforms (Datadog, New Relic, Elasticsearch, Grafana) to investigate issues and validate system behaviour

Knowledge of Domain-Driven Design (DDD) — bounded contexts, ubiquitous language, aggregate boundaries

📌 Senior QA Engineer (Madrid)
🏢 Cross River
📍 Madrid