Senior Development Full-Stack Engineer

## About the role We're a fast-growing fintech startup building secure, scalable financial systems—and we're looking for a Senior Development Engineer to help us design, operate, and optimize our external developer enablement. ## Responsibilities - Engineering Excellence: You will write reusable, reliable code that is performant and of high quality to support highly available, high-volume transaction processing systems. - Lead the design and execution of software projects, including independently designing and working on medium to large features. - Participate actively in the development lifecycle, including daily standups, sprint planning, estimating, and retrospectives. - Write unit tests and conduct thorough code reviews to ensure code quality. - Building and scaling high-quality, up-to-date resources including SDKs, tutorials, and code samples for external developers. - Authoring and maintaining best-in-industry documentation for mission-critical services. - Improving performance and efficiency across our developer portals and applications. - Embedding PCI DSS v4.0 compliance guidelines into external developer workflows and integration guides. ## Requirements - Strong hands-on experience with Ruby On Rails, API design, SDK development, and technical writing. - Proven experience working in regulated environments (PCI DSS or similar). - A mindset focused on ownership, performance, security, and developer success. - Deep expertise in creating intuitive, scalable technical enablement programs. - Affinity to learn new languages and AI Claude Code. ## Nice to have - Fintech or payments industry experience. - Experience with AWS, Azure, GCP. ## What we value - Ownership: You build it, you run it. ## About the company At IncumbentFI, we are reshaping the backbone of modern banking by building a highly secure, next-generation debit card transaction processing platform that seamlessly handles millions of real-time financial events. As a fast-growing financial technology startup operating a cutting-edge, multi-cloud architecture across AWS and Azure, we do the heavy lifting of complex data tokenization, robust encryption, and strict regulatory compliance so our partners can focus on innovation. What makes working here genuinely fun is the rare blend of high-stakes technical ownership and a collaborative, sandbox culture. You will work alongside a brilliant team of helpful, expert peers who respect the craft of engineering, solve complex distributed systems problems over coffee, and celebrate breaking down traditional industry silos without the weight of corporate bureaucracy.