Senior Software Engineer - Ruby on Rails (f/m/d)

Are you ready to change the market? At PAIR Finance we're building the AI-driven platform that's redefining debt collection across Europe.

We're looking for a senior software engineer who takes ownership end-to-end, is comfortable being the technical driver of a well-defined scope, and is energized by learning a deep, high-stakes domain: the legal processes around In-Court and After-Court debt collection.

Your Responsibilities: Own a clear scope end-to-e nd: take initiative from idea to production largely independently, and lead within your team (T-shaped: you go deep on your slice, and pair with one other developer) Design, build, and run POCs quickly to de-risk decisions before committing to a full build Develop, optimize, and maintain our core backend applications and services Work on high-level architecture to ensure scalability, performance, availability, and security Go deep on the In-Court/After-Court domain (the legal and procedural knowledge behind our collection processes is a core part of the job, not a side detail) Collaborate closely with product to shape the roadmap and unlock further company growth Work AI-augmented: you already use (or are ready to adopt) tools like Claude Code as part of how you build, review, and ship Help evolve and enhance our AI-based platform Stay current with industry trends and bring ideas back to the team What we're looking for: 5+ years of professional software engineering experience, including 1+ year on medium-to-large projects Strong backend experience in Ruby (Ruby on Rails) : this is our core stack, and required for the role Language-agnostic mindset: you pick the right tool for the job (hands-on experience with Go and/or Python is a big plus) Proven ability to work independently: scope, drive, and deliver a project with minimal hand-holding Experience with TDD and CI/CD A track record of writing clean, maintainable backend code and solid infrastructure Comfortable in an Agile environment ( Scrum, Kanban) Genuine inter