Staff Software Engineer, Backend at Flex in Remote

Summary: Flex is a growth-stage FinTech company based in New York City, aiming to transform the rent payment experience. The Staff Software Engineer, Backend will lead technical direction, mentor engineers, and design scalable backend services while collaborating with cross-functional teams. Responsibilities: - Design, build, and scale backend services and APIs that power Flex’s consumer apps, partner integrations, and core platforms - Provide technical leadership and guidance on system architecture, long-term vision, and team best practices - Lead the delivery of highly impactful products end-to-end, from requirements gathering to rollout, with high quality and timeliness - Work closely with product, design, and cross-functional teams to translate requirements into robust technical solutions - Build robust, fault-tolerant systems with multiple external dependencies in distributed environments - Drive adoption of best practices across the engineering org, including testing, observability, automation, and CI/CD - Mentor and support engineers on the team, raising the technical bar and fostering growth - Operate services in production with high availability, leveraging monitoring and observability tools - Contribute to evolving Flex’s service-oriented architecture, REST APIs, message queues, and scalable system design - Balance hands-on execution with architectural decision-making, ensuring velocity and long-term maintainability Required Qualifications: - 6–8+ years of professional software engineering experience, with a focus on backend development - 4+ years of hands-on Java experience (Spring core/web/boot, Gradle, JUnit, JVM tuning & performance) - Strong computer science fundamentals and proven experience designing scalable, distributed systems - Experience leading the delivery of multiple high-impact projects end-to-end - Skilled at working with both technical and non-technical stakeholders, aligning on scope and delivery - Ability to write high-quality, testable, maintainable, and secure code - Hands-on experience with AWS (EKS, Aurora RDS, Elasticache, DynamoDB), containerization (Docker/Kubernetes), and relational + NoSQL databases (MySQL, PostgreSQL, DynamoDB) - Proficient with CI/CD pipelines (GitHub Actions preferred), git, and build automation - Familiar with observability and monitoring tools (e.g., DataDog) for maintaining service availability - Excellent communicator, comfortable collaborating in globally distributed teams - Track record of mentoring engineers and raising team standards through best practices Preferred Qualifications: - Experience in FinTech and familiarity with major payment rails - Experience with big data platforms (e.g., Snowflake) - Infrastructure as Code (CDK/Terraform) Required Skills: Java, Backend development, AWS, Distributed systems Important Skills: CI/CD pipelines, Containerization Benefits: 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