Senior Software Engineer, Backend (Comms Core)

At Affirm, we exist for the moments that matter—giving people a clear, predictable way to pay over time, with no hidden fees, no surprises, and no tradeoffs on what matters most. About the Engineering team The Engineering team builds systems that power Affirm’s mission. We take pride in our craft, building reliable, performant, and scalable solutions that touch every part of the business. Whether we’re enabling new ways to pay, ensuring our platforms can scale to the most demanding levels in the industry, or developing seamless servicing experiences, our focus is on solving complex problems through exceptional engineering. About the team Affirm’s Communications team builds and modernizes the highly available platform that delivers billions of customer messages reliably and on time across the customer journey. As a senior backend engineer, you will shape multi-region, multi-tenant infrastructure, APIs, and vendor integrations that help product teams communicate with customers at scale. What you’ll do • You will own and deliver quarterly technical goals for the Communications area, collaborating with teammates to solve ambiguous, open-ended problems across messaging infrastructure. • You will design and evolve reliable backend services for high-volume communications across multi-region, multi-tenant environments, including orchestration, delivery, preferences, templates, and observability. • You will collaborate with product management, design, analytics, security, and engineering partners throughout the product lifecycle, articulating technical constraints and balancing customer impact, risks, and trade-offs. • You will design, implement, and operate resilient integrations with external messaging vendors, balancing reliability, latency, cost, and compliance. • You will proactively identify and solve project, process, technology, or business issues that affect scalability, developer experience, and operational resilience. • You will support the operations and availability of your team’s services by defining service-level objectives and metrics, improving alerting and incident response, and participating in on-call efforts. • You will foster quality and ownership by improving design, testing, code review, rollout, and operational standards, and advocating for them through writing and tech talks. • You will help develop talent on your team by providing feedback, mentorship, and technical direction, and leading by example. • On-Call Rotation - There would be an on-call rotation for this role as a requirement. What we look for • You have 5+ years of experience in software development or engineering, with a deep understanding of system design and architecture. • Proficiency in modern programming languages such as Python, Kotlin, or similar. • You have a track record of developing highly available distributed systems using technologies like AWS, MySQL, DynamoDB, and Kubernetes. • You have experience designing multi-region, multi-tenant platforms with strong isolation, scalability, failure recovery, and data-consistency guarantees. • You have experience integrating with third-party communications or messaging vendors and designing abstractions that account for different capabilities, rate limits, and failure modes. • You have experience defining a technical plan for the delivery of a significant feature or system component with an elegant, simple and extensible design. You write high quality code that is easily understood and used by others. • You are proficient at making significant changes in a large code base, and have developed a suite of tools and practices that enable you and your team to do so safely. • You are proficient with AI-assisted development tools and apply sound judgment to validate their outputs. • Your experience demonstrates that you take ownership of your growth, proactively seeking feedback from your team, your manager, and your stakeholders. • You have strong verbal and written communication skills that support effective collaboration with our global engineering team. Compensation & Benefits Pay Grade - N Equity Grade - 4 Employees new to Affirm typically come in at the start of the pay range. Affirm focuses on providing a simple and transparent pay structure which is based on a variety of factors, including location, experience and job-related skills. Base pay is part of a total compensation package that may include monthly stipends for health, wellness and tech spending, and benefits (including 100% subsidized medical coverage, dental and vision for you and your dependents). In addition, the employees may be eligible for equity rewards offered by Affirm Holdings, Inc. (parent company). ESP base pay range per year: €86,000 - €122,000 Additional benefits include: • Flexible Spending Wallets for tech, food and lifestyle • Away Days - wellness days to take off work and recharge • Learning & Development programs • Parental benefits • Employee Resource & Community Groups Location - Remote Spain We are able to offer visa sponsorship for this role, but do require that someone is based in Spain for the role. #LI-Remote Remote-first with flexibility built in Affirm is proud to be a remote-first company. Most roles can be done from almost anywhere within the country of employment. Some positions may occasionally require in-person work at an Affirm office, and a few are office-based due to the nature of the work. All new hires will be invited to attend an in-person onboarding experience. Benefits designed for you Our benefits reflect our commitment to care, transparency, and flexibility. Here are a few highlights: • Health coverage at no cost: We cover 100% of premiums for employees and their dependents. • Spending stipends: Monthly stipends support your tech setup, and the ability to choose health and wellness options that are right for you. • Time off to recharge: Flexible time off and generous holiday calendars help you rest