Senior Software Engineer, Backend (Test Enablers)

What You’ll Do

• Design, build, and maintain scalable systems for synthetic identities, test data seeding, mocking, load testing, and deterministic validation workflows.
• Help evolve Affirm’s testing strategy from broad E2E-heavy validation toward a more scalable model with stronger component, integration, contract, performance, and targeted E2E testing.
• Build platform capabilities that make production-like load testing safer, more repeatable, and easier to operate.
• Improve our test platform so it is reliable, observable, and easier for other teams to adopt.
• Partner with product engineering and infrastructure teams to improve test signal quality, reduce false failures, and support faster validation loops.
• Lead medium-to-large technical projects from ambiguous problem definition through design, implementation, rollout, and operational ownership.
• Improve reliability and operational maturity through dashboards, SLOs, alerts, runbooks, and clear ownership models.
• Reduce manual operational load for load testing, including test data creation, environment setup, reporting, and failure diagnosis.
• Write high-quality, maintainable code that can be easily understood and extended by others.
• Contribute to technical specs, RFCs, ADRs, project plans, and other async artifacts that align teams around technical decisions.
• Review code and technical designs, provide constructive feedback, and help raise engineering standards.
• Mentor engineers and help build a culture of practical testing excellence.

What We Look For

• 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.