Senior Software Engineer, Fullstack

Senior Software Engineer, Fullstack

Flex is a growth-stage, NYC headquartered FinTech company that is creating the best rent payment experience. It's hard to believe that it's 2025 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?

About The Job

Flex is looking for a Software Engineer (Fullstack) who will be responsible for implementing the various backend and frontend systems that support all business features.

In this role, you will be part of the product engineering team, responsible for the services and integrations that power our products, such as Payment, Billing, Identity, partner integration, and more. You'll be designing, developing, testing, and scaling systems needed to deliver great user and partner experiences.

You'll work closely with your product, design, and engineering peers to solve our users' most pressing problems around rent payment. You'll roll out changes to our customers in an agile manner with a delivery cadence that favors small, frequent iterations. The ideal candidate will be comfortable leading scoping, design, and implementation for APIs they build and can drive their production rollouts to completion with minimum oversight.

A minimum of 4+ years of experience with Java and 3+ with React / Typescript is required for this position.

Minimum Qualifications

• 6+ years of professional software development experience.
• 4+ years of hands-on experience with Java.
• 3+ years of experience with React or React Native.
• 3+ years of experience with TypeScript.
• Having experience building high-quality mobile and web UIs to specifications is a must to have.
• Ability to work on a globally-distributed team with a high degree of ownership.
• Experience working with technical and non-technical stakeholders, successfully aligning and setting expectations on scope and delivery.
• Ability to grow in a fast-paced and dynamic environment that will challenge you to always bring your best.
• Experience building robust, fault-tolerant systems with multiple external dependencies.
• Proficient in Java frameworks and tools used at Flex, including Spring (core / web / boot), Gradle, JUnit, and JVM (memory / performance tuning, GC).
• Experience with Service-Oriented Architecture, REST APIs, Message Queues, and scalable architectures.
• Experience with architectures and tools in React Native and React ecosystems (Hooks, Components, Context, Redux).
• Experience with AWS (EKS, Aurora RDS, Elasticache, DynamoDB) and containerization tools.

The salary compensation range for this role will be commensurate with the candidate's experience and Flex's internal leveling guidelines and benchmarks.

Life at Flex

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.

We offer many employee benefits. For full-time, U.S. based employees we offer :