Staff Software Engineer, Partner Integrations
External
Flex · WorldwidePrepare for this interview
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Responsibilities
- Design, implement, and maintain our payment integrations platform, including partner APIs, SDKs, and embedded web experiences
- Help shape and drive the technical roadmap for the Partner Engineering team
- Design and develop scalable APIs and integrations to support money movements across our banking partners via payment rails such as ACH
- Work cross-functionally with Engineering, Product, Design, Infrastructure, Sales, Partner, and Customer Success to deliver high-impact features
- Scale our integrations platform to support business growth while maintaining performance and reliability
- Continuously improve daily operations through automation, tooling, design evolution, and observability
- Mentor engineers and elevate team standards through best practices, code reviews, and technical guidance
Requirements
- Minimum 6 years of experience in software engineering
- Minimum 4 years of experience with Java; proficient in Spring (core/web/boot), Gradle, JUnit, and JVM tuning
- Experience with Service-Oriented Architecture, REST APIs, message queues, and scalable distributed systems
- Experience with AWS (EKS, Aurora RDS, Elasticache, DynamoDB) and containerization
- Experience leading delivery of multiple high-impact products end to end, on time with a high quality bar
- Ability to work on a globally-distributed team with a high degree of ownership
- Experience aligning technical and non-technical stakeholders on scope and delivery
- Experience in FinTech and familiarity with major payment rails
- Ability to drive quality and consistency across your team without compromising velocity
- Proficient in CI/CD systems (preferably GitHub Actions) and automation
- Skilled in observability and monitoring tools such as DataDog
- Experienced with big data platforms including Snowflake
- Proficient in Infrastructure as Code (CDK, Terraform)
- Excellent written and verbal communicator with cross-functional collaboration experience
Benefits
Additional Information
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 2026 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? As we continue to grow our talented team, we remain committed to radical transparency, integrity, and individual growth. We believe that your unique background and experience adds tremendous value to the organization and will empower you to take absolute ownership of business challenges and the execution of solutions. What we need: Flex is looking for a Staff Software Engineer to join our Partner Engineering organization and help build out our payment integrations platform & user experiences. You will help shape the technical roadmap for the team, working across APIs, SDKs, and Web experiences. You will work with teams across the organization including Engineering, Product, Design, Infrastructure, Sales, Partner and Customer Success to deliver products that wow our customers and drive business goals. We expect you to be hands-on and execute work as an individual, and build products that allow for flexibility as we evolve our product offerings.
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