Senior Software Engineer, Fullstack (Repayments UX)

Affirm, Inc.; Comunidad de Madrid; Remote; EUR 86,000 - 122,000; Full time

Benefits offered by this job

Health coverage for employees and pre/

Equity rewards

Flexible Spending Wallets

Away Days

Learning & Development

Parental benefits

Employee Resource & Community Groups

Job summary

Affinist, a remote-first company operating across Europe, seeks a Senior Full-Stack Software Engineer for the Repayments UX team. You will own quarterly goals, guide engineers, and drive scalable features across web and mobile platforms.

The role requires 4+ years of experience with React Native and web frameworks, plus backend skills in Python or Kotlin. We offer equity, health coverage, stipends, and visa sponsorship for Spain-based hires.

Qualifications

• 4+ years of experience developing and architecting mobile apps (preferably with React Native).
• Experience shipping web apps using React or Vue.
• Proficient in Python or Kotlin for backend work.
• Strong verbal and written communication skills for global collaboration.

Responsibilities

• Own and deliver quarterly goals for the team and guide engineers through ambiguity.
• Collaborate with product, design and analytics across the full product lifecycle.
• Proactively identify and solve project, process, or technology issues.
• Monitor metrics and support on-call duties to keep systems reliable.

Skills

React Native

React or Vue

Python or Kotlin

Strong communication

Ownership mindset

Job description

Senior Software Engineer, Fullstack (Repayments UX)

Remote Spain

At Affinist 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 Repayment UX Engineering team is growing, and we're looking for a Senior Full-Stack Software Engineer. We're a full-stack team located entirely in Europe within the same time zone, but culturally rooted in Silicon Valley. We directly improve the financial lives of over 20 million people. We build and own user journeys that enable them to pay back loans worth collectively over $40B each year. Our team exists to make these moments the most reliable and transparent in world-class consumer finance.

Our work is agile and fast-paced and we rigorously measure the impact it has on the behavior of our users. This role rewards curiosity, ownership, and a builder's mindset. You'll know exactly what your objectives are, you'll have what you need to hit them, and you'll choose your own path to get there. You'll learn quickly from experienced teammates and grow your craft on problems that matter at scale. If you want to build something new and operate it at scale – come join us!

What You'll Do

• You will be responsible for owning and delivering quarterly goals for your team, leading engineers on your team through ambiguity to solve open-ended problems, and ensuring that everyone is supported throughout delivery.
• You will support your peers and stakeholders in the product development lifecycle by collaborating with product management, design & analytics by participating in ideation, articulating technical constraints, and partnering on decisions that properly consider risks and trade-offs.
• You will proactively identify project, process, technology or business issues, advocate for them, and lead in solving them.
• You will support the operations and availability of your team’s artifacts by creating and monitoring metrics, escalating when needed, and supporting “keep the lights on” & on-call efforts.
• You will foster a culture of quality and ownership on your team by setting or improving code review and design standards for your team, and advocating for them beyond your team through your writing and tech talks.
• You will help develop talent on your team by providing feedback and guidance, 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 4+ years of experience of developing and architecting mobile applications, preferably using declarative UI frameworks like React Native.
• You have experience shipping web apps using declarative UI frameworks like React or Vue.
• You have experience designing, developing and launching backend systems and are proficient in one of Python or Kotlin.
• Experience developing and architecting mobile applications, preferably using declarative UI frameworks like React Native is a bonus.
• 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.
• 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 Affinist typically come in at the start of the pay range. Affinist 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 Affinist 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.

Remote-first with flexibility built in

Affinist 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 Affinist 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 Affinist 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: Affinist considers qualified applicants with arrest and conviction records, as required by law.