Senior Fullstack Engineer - User Retention & App Ecosystem

Kikoff; San Francisco (CA); On-site; USD 244,000 - 292,000; Full time

Job summary

Kikoff is seeking a Senior Fullstack Engineer to drive user-facing projects and scale our growing fintech ecosystem. You will own critical product domains end-to-end and collaborate across teams to improve reliability and observability.

Join a fast-moving, high-impact team building software that helps millions move forward financially. The role emphasizes ownership, collaboration, and delivering data-driven features at scale.

Qualifications

• 6+ years of industry experience with breadth and depth of product impact.
• Strong backend focus with web frontend (React) or mobile (Flutter).
• Ability to own complex end-to-end projects with cross-functional teams.
• Experience with financial infrastructure or regulated environments (credit bureau data, PII, SOC2).
• Experience with APIs integration and production ML deployment.

Responsibilities

• Lead data-driven projects around user retention and ecosystem integration end-to-end, affecting millions of users.
• Own 1 to 2 large product areas across credit report retrieval, credit disputes, customer off-boarding experience, and cross-app integration.
• Enhance observability, reliability, and operational excellence across existing services.

Skills

Cross-functional

System design

End-to-end ownership

Observability

Communication skills

AI tooling

Team mentorship

APIs integration

Education

B.A./B.S./M.S. in CS

Self-taught fundamentals in CS

Tools

Ruby on Rails

React

Flutter

MySQL

Job description

Kikoff: The Fintech Powering Financial Security at Scale

Kikoff is a profitable, pre-IPO fintech company on a mission to empower everyone to achieve financial security. With record revenue growth in 2025 and a unicorn valuation, we've built a suite of products that help millions of people build credit, access liquidity, and save money.

We're scaling fast. Join us if you want to build something meaningful and help millions of people move forward financially.

Why Kikoff

This is a consumer fintech startup, and you will be working with serial entrepreneurs who have built strong consumer brands and innovative products. We value extreme ownership, clear communication, a strong sense of craftsmanship, and the desire to create lasting work and work relationships. Yes, you can build an exciting business AND have real-life real-customer impact.

About The Team

The User Retention and App Ecosystem team focuses on sustainable, long-term, and interconnected customer growth at Kikoff. We help customers stay around longer and get more value from their subscriptions. We ensure that customers are excited to explore the different consumer fintech apps across Kikoff’s growing ecosystem, with as little cross-app friction as possible.

We’re looking for a Senior Fullstack Engineer to drive user-facing projects, improve existing core services, and own product domains. If you like owning both the work and the outcome of a complex project end-to-end, we’d like to talk to you!

What you’ll be doing

• Lead and implement data-driven and impact-focused projects around user-retention and ecosystem integration end-to-end, affecting millions of users.
• Be the definitive technical owner for 1 to 2 large product areas across credit report retrieval, credit disputes, customer off-boarding experience, and cross-app integration.
• Enhance observability, reliability, and operational excellence across existing services.

What we’re looking for

• B.A. / B.S. / M.S. or strong self-taught fundamentals in computer science
• 6+ years of industry experience, or high-slope growth, with demonstrated breadth and depth of product impact
• Strong fullstack development experience with a backend focus: proficient or highly proficient on the backend, and experienced in either web frontend (React) or mobile (Flutter preferred)
• Strong cross-functional communication and coworking skills with product, data, design, and legal partners
• Demonstrated ability to own and drive complex projects end-to-end, coordinating focused teams through ideation, requirements, design, implementation, launch, and post-launch.
• Good judgment in identifying and choosing trade-offs between business impact, delivery speed, and long-term operational excellence
• Strong system design skills for both new and existing systems

An ideal candidate also shows

• Experience with financial infrastructure or regulated environments (credit bureau data, PII, SOC2)
• Background in fintech, payments, or lending infrastructure
• Experience integrating third-party APIs reliably and communicating with technical vendors
• Experience with classical ML model training and production deployment
• Experience with observability, monitoring, and alarms in customer-facing systems
• Experience with using business metric focused A/B tests and experiments for new features
• Experience in leveling up the team through code reviews, design docs, and technical guidance
• Thoughtful use of AI tools to accelerate delivery while maintaining operational excellence
• Eagerness for product and feature ideation
• Experience with our stack is a plus: Ruby on Rails, React, Flutter, MySQL

Base Range

$244,000 - $292,000 USD

Equal Employment Opportunity Statement

Kikoff Inc. is an equal opportunity employer. We are committed to complying with all federal, state, and local laws providing equal employment opportunities and considers qualified applicants without regard to race, color, religion, creed, gender, national origin, age, disability, veteran status, marital status, pregnancy, sex, gender expression or identity, sexual orientation, citizenship, or any other legally protected class.

Please reference the following for more information.