Staff Software Engineer, Backend

Flex is a growth-stage FinTech company headquartered in NYC, focused on creating a seamless rent payment experience. They are seeking a Staff Software Engineer, Backend to lead technical direction, mentor engineers, and collaborate across teams to build scalable and reliable backend services.

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

Requirements:

• 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
• Experience in FinTech and familiarity with major payment rails
• Experience with big data platforms (e.g., Snowflake)
• Infrastructure as Code (CDK/Terraform)