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Salary: USD 173,000 - 255,000 / annual
Affirm is seeking a Senior Fullstack Software Engineer to join the Acquisition & Onboarding team within the Consumer organization. This is a high-impact role for an engineer who can set technical direction, drive architectural decisions, and elevate the quality and velocity of full stack development across mobile, web, and backend systems.
The team plays a critical role in shaping the first experience customers have with Affirm—building trust, clarity, and value from the very first interaction. As a Senior Engineer, you will be responsible for defining long-term technical strategy, mentoring senior engineers, and acting as a force multiplier through your technical depth, operational excellence, and ability to navigate ambiguity. You'll work at the intersection of product, design, and engineering to build polished, performant, and accessible user experiences that directly impact conversion, retention, and business growth.
Key responsibilities include owning and delivering quarterly goals for your team, leading engineers through ambiguity to solve open-ended problems, and ensuring team support throughout delivery. You'll collaborate with product management, design, and analytics, participating in ideation and articulating technical constraints. You'll take ownership of your team's operations and availability by ensuring proper monitoring, triage rotations, playbooks, policies, testing, and alerting. You'll proactively identify project, process, technology, or business issues, advocate for them, and lead in solving them. You'll foster a culture of quality and ownership by setting or improving code review and design standards, and help develop talent on your team through feedback and guidance.
Required experience includes leading significant mobile initiatives (React Native or native), working across React Native and native boundaries (Swift/Kotlin), implementing experimentation and feature flagging in mobile applications, shipping web apps using React or Vue, proficiency in JavaScript/TypeScript, 4+ years as a software engineer, designing and launching backend systems at scale using Python, Kotlin, AWS, MySQL, and Kubernetes, and defining technical plans for significant features with elegant, simple, and extensible designs. You should demonstrate strong ownership of your growth, proactive feedback-seeking, and excellent verbal and written communication skills.
