Senior Software Engineer, Backend

Flex is hiring a Senior Engineer to join our backend engineering team, where you'll be responsible for designing, building, and scaling the systems that power our core products — including Payments, Billing, Identity, and partner integrations. You'll work on services that directly shape how hundreds of thousands of renters experience financial flexibility, and your work will have a measurable impact on the reliability and performance of everything we ship.

In this role, you'll own meaningful portions of our backend infrastructure end-to-end — from scoping and API design through production rollout — with the autonomy to make independent technical decisions that drive real customer and business impact. You'll collaborate closely with product, design, and engineering peers in an agile environment that favors small, frequent iterations over big-bang releases. The ideal candidate is comfortable leading without being asked and takes pride in shipping high-quality, fault-tolerant systems.

At Flex, engineers are expected to bring both technical depth and a builder's mindset. You'll be working within a globally distributed team, partnering with technical and non-technical stakeholders alike, and contributing to a codebase that scales with an ambitious product roadmap. If you thrive in fast-moving environments and want your engineering work to directly improve how people pay rent, this role is for you.

• →Own multiple backend team goals and projects, delivering on time and with high quality with minimal oversight
• →Design, build, and scale backend services and APIs across core domains including Payments, Billing, Identity, and partner integrations
• →Make independent technical decisions that maximize customer and business impact, balancing speed with long-term system health
• →Write elegant, well-tested code and provide constructive, thorough code reviews that elevate team standards
• →Lead scoping and design discussions for new features and systems, driving production rollouts to completion
• →Integrate AI-assisted development tools into your daily workflow as a default, and mentor teammates on responsible and effective AI usage
• →Partner with product, design, and cross-functional engineering peers to solve high-priority user problems around rent payment
• →Contribute to observability, reliability, and performance standards across the services you own

• 6+ years of software engineering experience, with at least 4 years of hands-on Java development
• Proficiency in Java frameworks and tooling including Spring (core/web/boot), Gradle, JUnit, and JVM tuning (memory, performance, GC)
• Experience designing and building robust, fault-tolerant systems with multiple external dependencies using Service-Oriented Architecture, REST APIs, and message queues
• Hands-on experience with AWS services (EKS, Aurora RDS, ElastiCache, DynamoDB) and containerization tooling
• Comfort working on a globally distributed team with a high degree of ownership and strong stakeholder communication skills
• Experience with CI/CD systems (preferably GitHub Actions), git, and automation practices
• Familiarity with observability and monitoring tools such as Datadog to maintain high availability
• Consistent use of AI-assisted development tools (code generation, test writing, documentation) with full ownership of correctness, security, and quality

#LI-Remote

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.

Roles posted in New York, San Francisco, and Salt Lake City are hybrid positions with on-site expectations of 2-3 days per week in our local offices. For candidates outside of these areas, you may be eligible for our relocation assistance program.