Senior Software Engineer, Backend (Card Loan Platform)

Remote; San Francisco (CA); Remote; USD 173,000 - 255,000; Full time

Benefits offered by this job

100% subsidized medical coverage

Tech stipends for setup

Flexible time off

Employee stock purchase plan

Job summary

Affirm is building the financial backbone for card products with a remote-first culture and high-traffic distributed systems. You will design and implement large-scale services, APIs, and data models, partnering with product, data science, and engineering teams to deliver robust, scalable solutions for real-time payments.

You will mentor engineers, drive technical decisions, and contribute to a culture of excellence while growing with a fast-moving, globally distributed team.

Qualifications

• 5+ years of software development or engineering experience.
• Proven leadership and the ability to grow a team.
• Excellent communication across diverse audiences.
• Strong analytical and problem-solving mindset.
• Proficient in Python or Kotlin; cloud and container knowledge.

Responsibilities

• Drive technical strategy by leading planning, prioritization, and execution of projects.
• Lead end-to-end design and development of large-scale services, APIs, and data models.
• Collaborate with Product, Analytics, Design, Legal, and Accounting to define requirements for card loan attribution and lifecycle.
• Ensure system health and performance by analyzing issues and optimizing code for long-term robustness.
• Mentor engineers, lead design reviews, and promote best practices.

Skills

System design

Leadership

Communication

Problem solving

Python

Kotlin

Cloud computing

Education

Bachelor’s degree in related field

Tools

Docker

Kubernetes

AWS

Azure

Google Cloud

SQL

NoSQL

RESTful APIs

Job description

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.

The Card Loan Platform team builds the high-throughput decision engine at the heart of affirm’s card products. Unlike traditional cards, every pay-later transaction is backed by its own unique loan, and our system is the "invisible piping" that makes this complex model work at scale. Every swipe triggers our platform to solve a hard problem in milliseconds: matching messy, fragmented payment network data to the correct loan to drive real-time approvals, origination, and refunds.

As affirm experiences explosive growth, our team's contributions are a key enabler. This isn't just another backend role; you'll be building the "financial brain" for our flagship card products, with your work on the critical path for every single swipe. We're tackling a unique, high-stakes distributed systems challenge that demands exceptional correctness and massive scale. You will partner closely with product, data science, and engineering teams to design and build the future of our industry-leading money movement platform.

If you are passionate about making foundational design decisions and building a beloved, lasting financial brand—come join us. It’s going to be an amazing ride!

What you'll do

• Drive technical strategy by leading the planning, prioritization, and execution of projects, ensuring alignment with product, technical, and business goals.
• Lead the end-to-end system design and development of large-scale, high-availability services. This includes building robust APIs and data models for our micro-service and event-driven architectures.
• Collaborate across functions with partners in Product, Analytics, Design, Legal, and Accounting and to define requirements and execute our card loan attribution and lifecycle strategy.
• Ensure system health and performance by analyzing and troubleshooting complex technical issues, optimizing existing code, and driving solutions that focus on long-term robustness and scalability.
• Mentor and grow the team by guiding junior engineers, leading technical discussions and design reviews, and championing best practices through code review.

What we look for

• 5+ years of experience in software development or engineering, with a deep understanding of system design and architecture.
• Motivated leader, inspiring team growth and fostering a culture of continuous learning
• Excellent communicator, adept at sharing complex ideas with diverse audiences.
• Strong analytical and problem-solving skills, with a creative and solution-oriented mindset.
• Proficiency in modern programming languages such as Python, Kotlin, or similar.
• Experience with cloud platforms (AWS, Azure, Google Cloud) and containerization (Docker, Kubernetes).
• Knowledge of database systems (SQL, NoSQL), web frameworks, and RESTful API development.
• This position requires either equivalent practical experience or a Bachelor’s degree in a related field.

Base Pay Grade - N

Equity Grade - USA 9

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 equity rewards, monthly stipends for health, wellness and tech spending, and benefits (including 100% subsidized medical coverage, dental and vision for you and your dependents.)

USA Pacific base pay range (CA, WA, NY, NJ, CT): $195,000 - $255,000

USA Sapphire base pay range (all other U.S. states): $173,000 - $233,000

#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 when you need to.
• Own a piece of what you build: Our employee stock purchase plan (ESPP) lets you buy affirm stock at a discount.

We’re committed to providing an inclusive interview process, including accommodations for candidates with disabilities. If you need support, we’re happy to help.

For positions based in San Francisco or Los Angeles: affirm considers qualified applicants with arrest and conviction records, as required by law.