light-inc - Software Development Engineer in Test (SDET)

• Build the Infrastructure: Design and implement test frameworks, fixtures, and data management patterns that make good testing the path of least resistance across multiple languages and frameworks. Immediate focus is TypeScript, Kotlin, Python, and Terraform. • Solve Test Data: Build strategies for realistic, safe test data in a fintech context — synthetic data generation, anonymisation, and environment management that lets engineers test confidently without touching production data. • Define the Standard: Create the "paved road" for product engineers — standardising how every team at Light writes, runs, and maintains tests. Own the testing section of our engineering playbook. • Solve for Trust: Build quality gates in CI/CD that catch problems before production. Implement test observability so failures are obvious and actionable, not cryptic and ignored. • Bridge the Gap: Write tests in high-risk areas where coverage is critical — not as permanent ownership, but to model good practice, stabilise production, and demonstrate what good looks like. • Scale the Culture: Coach engineers across all teams on test design and help them adopt new practices. Your success is measured by how quickly quality ownership distributes to delivery teams. • Test the Non-Deterministic: Build evaluation frameworks for AI features — prompt regression testing, golden datasets, and reliability metrics that let us deploy AI with the same confidence as traditional code. • Test Engineering Background: You have significant experience building test infrastructure and tooling, not just writing tests. You understand the difference between unit, integration, and E2E testing — and when each matters. • Polyglot Capabilities: You are comfortable working across multiple languages. Our stack includes Kotlin, TypeScript, and Python. Mastery of all three is not required, but resistance to learning is a dealbreaker. • Platform Mindset: You get more satisfaction from unblocking 10 engineers with a great tool than from shipping a single feature yourself. You think in systems, not tasks. • Focus on Reliability: You hate flaky tests. You understand that trust is the biggest bottleneck to test adoption, and you know how to build the observability and diagnostics necessary to generate that trust. • Coaching Instinct: You can influence without authority. You will be changing how teams work, and that requires patience, clarity, and credibility earned through doing the work alongside them. • AI Testing Experience: You have built evaluation frameworks for LLM-based systems. You understand the challenges of testing non-deterministic outputs — golden datasets, semantic similarity, human-in-the-loop evaluation, prompt regression. You know why traditional assertions don't work and what to use instead. • Useful but not essential • Experience in high-growth startups where quality culture had to be built, not inherited • Familiarity with GitHub Actions or similar CI/CD platforms • Background in fintech or systems where data integrity is non-negotiable • Experience with contract testing, property-based testing, or complex integration scenarios • We are hiring at both Mid and Senior level for this role. Senior candidates will ship high-impact work, drive strategy, and coach across the organisation. Mid-level candidates will execute within that strategy and grow into broader ownership. • In addition to being part of a great team and working in a really fun and innovative environment, we offer: • 💸 A competitive salary + potential stock options • 🏝 25 days of annual leave + public holidays in the country where you are based. • 🥳 Regular socials and company off-sites • 🚀 A huge opportunity for career growth as you'll help shape a market-defining product. • The famous last words • Working at Light means you're embarking on an exciting journey to reshape the future of multinational financial operations. Our cheat-code is that we've built something like this before - and are now doing it again, only better. Our goal is to make global finance effortless and empower companies to make informed decisions.