Software Engineer II, Backend

Summary

Join Flex, a NYC-based FinTech company revolutionizing rent payments, as a Software Engineer II, Backend. You'll be part of a team designing, building, and scaling backend services and APIs for consumer products, partner integrations, and core business systems. This role involves the entire service lifecycle, from architecture to deployment and monitoring. You will collaborate with cross-functional teams to deliver impactful solutions. Flex offers competitive pay, comprehensive benefits, and a dynamic work environment. The position is available across three engineering teams: Consumer, Partner Integrations, and Core Platform, with placement determined by experience and expertise.

Requirements

• Strong computer science fundamentals and passion for building scalable backend systems
• 2–3+ years of professional software engineering experience with a focus on backend services
• Proficient in Java with hands-on experience using Flex’s core stack: Spring (core/web/boot) , Gradle , JUnit
• Experience building and maintaining distributed services and APIs at scale in production environments
• Familiar with REST API design, mobile API best practices, and service-oriented architectures
• Experience building fault-tolerant systems with multiple external dependencies
• Skilled in observability and monitoring tools (e.g., DataDog ) to ensure high availability
• Ability to write high-quality code that is testable, maintainable, scalable, and secure
• Demonstrated ability to translate business requirements into technical specifications and deliver high-impact solutions
• Excellent communicator who thrives in a collaborative, globally-distributed team environment
• Comfortable working with both technical and non-technical stakeholders and setting expectations on scope and delivery

Responsibilities

• Design, develop, test, and scale backend services and APIs that power Flex’s products, partner experiences, and internal platforms
• Implement the service APIs used by our mobile and web apps to simplify complex rent payment processing
• Build robust, fault-tolerant systems that integrate with multiple external dependencies and ensure high reliability
• Work closely with cross-functional teams—including Engineering, Product, Design, Infrastructure, Sales, Partner, and Customer Success—to deliver features and integrations that wow both customers and partners
• Translate feature requirements into well-structured technical specifications and scalable solutions
• Lead scoping, design, and implementation for the APIs you build and drive production rollouts with minimal oversight
• Contribute to service-oriented architecture, scalable system design, and internal best practices for distributed services environments
• Collaborate with peers to evolve Flex’s technical architecture as the company and product offerings grow
• Ensure services are observable and highly available through effective use of monitoring tools and practices
• Participate in code reviews, CI/CD improvements, and efforts to increase code quality and stability

Benefits

• Competitive pay
• 100% company-paid medical, dental, and vision
• 401(k) + company equity
• Unlimited paid time off + 13 company paid holidays
• Parental leave
• Flex Cares Program: Non-profit company match + pet adoption coverage
• Free Flex subscription
• Competitive Pay
• Company Equity
• Unlimited PTO