Staff Software Engineer, Backend (Card) (Fintech)

TL;DR

Staff Software Engineer, Backend (Card) (Fintech): Leading the architecture and technical strategy for EU card systems, including millisecond-scale transaction processing, ledgering, and reconciliation with an accent on scalable backend platforms and cross-functional execution. Focus on designing resilient payment infrastructure, solving complex distributed-systems challenges, and improving operational reliability across EU engineering teams.

Location: Remote from Spain; visa sponsorship is available, but candidates must be based in Spain.

Salary: €103,000–€139,000 gross base pay per year.

Company

Affirm is a fintech company developing transparent credit and flexible buy-now-pay-later and card products.

What you will do

• Set the team’s technical strategy over a year-long horizon and connect it to business-critical projects.
• Lead software engineering for EU card products and define architecture across card systems.
• Design and improve real-time transaction processing, ledgering, reconciliation, and other payment infrastructure.
• Collaborate with product management, design, and analytics to manage technical risks and trade-offs.
• Own operational availability through monitoring, testing, alerting, playbooks, and on-call processes.
• Raise engineering quality through code reviews, design standards, technical writing, mentoring, and talent development.

Requirements

• 8+ years of professional software engineering experience.
• Strong backend development experience with Python, Kotlin, AWS, MySQL, and Kubernetes.
• Experience developing frontend applications.
• Experience delivering major system features, components, or deprecations through technical and execution plans.
• Ability to work from low-level language details through large-scale system architecture and operate effectively in ambiguity.
• Strong written and verbal English communication skills; candidates must be based in Spain.

Culture & Benefits

• Remote-first work within the country of employment.
• 100% subsidized medical, dental, and vision coverage for employees and dependents.
• Flexible spending wallets for technology, food, lifestyle, and family-forming expenses.
• Wellness days, competitive vacation and holiday schedules, and parental benefits.
• Learning and development programs, employee resource groups, and an employee stock purchase plan.