Senior Software Engineer, Backend (Test Enablers) 100% remote)

Affirm is a company focused on reinventing credit to provide honest and friendly financial products without hidden fees or compounding interest. The role is within the Test Enablers team of Test Platform Engineering, which builds and operates platforms for testing, including synthetic identities, test data seeding, mocking, deterministic testing workflows, and load testing. The Developer Productivity division aims to dramatically accelerate software development and improve system reliability at Affirm.

• 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 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 engineering fundamentals across system design, testing, debugging, reliability, and production operations.
• Operational ownership experience of critical internal testing platforms.
• Experience with test automation frameworks, test data systems, mocks, contract testing, integration testing, load testing, and CI/CD platforms.
• Ability to balance pragmatic 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 from broad E2E-heavy validation toward scalable component, integration, contract, performance, and targeted E2E testing.
• Build platform capabilities for safer, repeatable, and easier to operate production-like load testing.
• Improve test platform reliability, observability, and ease of adoption by other teams.
• Partner with product engineering and infrastructure teams to improve test signal quality, reduce false failures, and speed up validation loops.
• Lead medium-to-large technical projects from problem definition through design, implementation, and operational ownership.
• Enhance reliability and operational maturity through dashboards, SLOs, alerts, runbooks, and ownership models.
• Reduce manual operational load for load testing including data creation, environment setup, reporting, and failure diagnosis.
• Write high-quality, maintainable code.
• Contribute to technical specifications, RFCs, ADRs, project plans, and other documentation.
• Review code and technical designs, provide feedback, and raise engineering standards.
• Mentor engineers and promote a culture of testing excellence.

This job description is not a contractual document and is not intended to have binding force. The majority of roles can be located anywhere in Poland. Data controller information and candidate data rights are provided by Affirm as per legal requirements.