Senior Software Engineer, Backend (Test Enablers)

Affirm is reinventing credit to make it more honest and friendly, giving consumers the flexibility to buy now and pay later without any hidden fees or compounding interest. The role is within the Test Enablers team in Test Platform Engineering, focused on developer productivity. Affirm's mission is to dramatically accelerate software development while keeping systems reliable, aiming to scale to 1,000 PRs per day by December 2027.

• 5+ years of software engineering experience.
• Strong backend engineering experience with Python, Kotlin, Java, or similar languages.
• Experience designing, building, and operating distributed systems, platform infrastructure, internal developer tools, or testing infrastructure.
• Strong ownership and ability to independently drive ambiguous technical work to completion.
• Experience improving system reliability, observability, operational maturity, and maintainability.
• Ability to collaborate across engineering teams and influence technical direction through clear communication.
• Excellent written and verbal communication skills, including async artifacts such as technical specs, RFCs, ADRs, and project plans.
• Strong fundamentals in system design, testing, debugging, reliability, and production operations.
• Operational ownership of critical internal testing platforms including reliability, observability, alerting, runbooks, and incident readiness.
• Experience with test automation frameworks, test data systems, mocks, contract testing, integration testing, load testing and CI/CD platforms.
• Ability to balance practical delivery with long-term technical quality.
• Passion for improving developer productivity and product quality through scalable, automated, reliable systems.

• Design, build, and maintain scalable systems for synthetic identities, test data seeding, mocking, load testing, and deterministic validation workflows.
• Evolve Affirm’s testing strategy towards scalable component, integration, contract, performance, and targeted E2E testing.
• Build safer, repeatable, and easier to operate production-like load testing platform capabilities.
• Improve test platform reliability, observability, and adoption by other teams.
• Partner with product engineering and infrastructure teams to improve quality and speed of test signals.
• Lead medium-to-large technical projects from problem definition through operational ownership.
• Enhance reliability and operational maturity via dashboards, SLOs, alerts, runbooks, and ownership models.
• Reduce manual operational effort for load testing, including test data creation and failure diagnosis.
• Write maintainable, high-quality code.
• Contribute to technical specifications, RFCs, ADRs, and project plans.
• Review code and designs; provide constructive feedback.
• Mentor engineers and foster a culture of testing excellence.

This is a remote-first role located within Poland. Affirm provides reasonable accommodations for candidates with disabilities during hiring. The job description is not a contractual document and is not legally binding.