Senior Software Engineer, Backend (Card)

About the Role

Affirm is building a new generation of transparent credit products, working directly with card issuers to reshape how credit is used globally. In this Senior Software Engineer, Backend role focused on Card systems, you'll own critical infrastructure spanning real-time transaction processing and post-transaction ledgering and reconciliation—some of the most technically demanding work at Affirm. You'll lead a backend engineering team from our Spain office, driving quarterly goals and mentoring engineers through complex, open-ended problems.

Responsibilities

• Own and deliver quarterly team goals; lead engineers through ambiguous technical challenges and ensure team support throughout delivery
• Collaborate with product management, design, and analytics during ideation and decision-making; articulate technical constraints and evaluate risks and trade-offs
• Identify and advocate for solutions to project, process, technology, and business issues
• Ensure operational excellence and availability of team systems by creating and monitoring metrics, escalating issues, and participating in on-call rotations
• Drive a culture of quality and ownership through code review standards, design practices, and knowledge sharing across the organization
• Develop team talent through feedback, guidance, and leading by example
• Participate in required on-call rotation for incident response and system reliability

Requirements

• 4+ years of software engineering experience
• Proven expertise designing, developing, and launching backend systems at scale using Python, Kotlin, AWS, MySQL, and Kubernetes
• Experience shipping frontend applications
• Demonstrated ability to define technical plans for significant features or system components with elegant, simple, and extensible designs
• Strong code quality practices; ability to write code that is clear and usable by others
• Proficiency making significant changes in large codebases with well-developed testing approaches

Benefits

Remote position based in Spain.