Senior Software Engineer, Mobile & Web

Flex is a growth-stage, NYC headquartered Fin Tech company that is creating the best rent payment experience. It’s hard to believe that it’s 2026 and paying rent on time is expensive, inflexible, and difficult. We’re here to change that! Flex enables our users to pay rent throughout the month on a schedule that better fits their finances and budget. Our mission is to empower as many renters as possible with flexibility over their most significant recurring expense.

After deliberately keeping a stealth profile as we built up unprecedented investor support and an enthusiastic user base, we are looking for motivated individuals to help us keep our mission growing. Will you be a part of the team?

Flex is looking for a Senior Software Engineer that will be responsible for the development of our core user experience across our mobile and web platforms.

In this role you will be working closely as part of a team to launch new features across our web and mobile platforms. You’ll be developing, designing, testing, and scaling new product offerings that solve complex problems in a simple way for all of our users.

In this role, you can expect to be working closely with other cross functional partners across our organization on a daily basis. Our team works in an agile manner, and some of the partners you can expect to work with in this role include designers, product managers, and quality engineers. We expect you to be able to be hands‑on and execute on work as both an individual, while also building products that allow for flexibility as we are evolving our product offerings.

A minimum of 4 years experience in React.js or React Native is required for this position.

• Strong computer science fundamentals
• A strong focus on building high quality mobile and web UIs to specifications
• Experience with various architectures and tools within the React Native and React ecosystems (Hooks, Components, Context, Redux)
• Experience leading and delivering products at a large scale without performance bottlenecks (hundreds of thousands to millions of users)
• Write maintainable code that uses industry best practices to improve the entire software development life cycle (unit testing, linting, automation)
• Ability to write well‑documented and testable Type Script code
• Familiarity with REST APIs and tooling across web and mobile architectures
• Collaborating with engineers across multiple teams to improve code quality
• Able to mentor engineers in using best practices for software development

• Prior experience working on cross functional teams
• Proficient with Type Script (Bonus: Native iOS/Android)
• Experience with CI/CD to improve code stability and code quality
• Experience with IDEs such as VSCode, Android Studio, XCode
• Familiar with Android / iOS / Web development tool ecosystem
• Motivated to help other engineers succeed and be effective

Flex takes a market‑based approach to pay, and compensation may vary depending on your primary work location. Work locations are categorized into one of three tiers based on a cost of labor index for that geographic area. The successful candidate’s starting pay will be commensurate with their experience, qualifications, and Flex’s internal leveling guidelines and benchmarks.

• Tier A (NYC/SF/Seattle): $172,000—$210,000 USD

We understand that it takes a diverse team of highly intelligent, curious, determined, empathetic, and self‑aware people to grow a successful company. Our HQ is located in New York City, but we have employees located throughout the US, Australia, Canada and South America. We are growing quickly, but deliberately, with a focus on building an inclusive culture. Our dynamic team has incredible perspectives to share, just as we know you do, and we take great pride in being an equal opportunity workplace.

• Competitive medical, dental, and vision available from Day 1
• Company equity
• 401(k) plan with company match (our company match kicks off at the beginning of 2026)
• Unlimited paid time off + 13 company paid holidays
• Parental leave
• Flex Cares Program
• Free Flex subscription
• Competitive compensation + company equity for full‑time non‑US…