Full-Stack API Developer

Remote work: 100% remote. Project language: German + English. Start: ASAP/2 weeks. Assignment type: B2B – up to 45 EUR/h. Project length: first contract until the end of the year, then regular extensions 6-12 months. Onboarding: 1 week on-site in Hanover. Additional visits: once every 2-3 months for 3 days on demand. Workload: full time (40 hours per week). Industry: Finance. Summary: The Full-Stack API Developer is responsible for integrating Hypoport’s advisory engine. This role aims to enhance existing systems and support clients with technical integration, fostering collaboration within a distributed agile team. Main Responsibilities: Develop and integrate REST API interfaces into existing systems. Implement technical requirements within a large-scale integration and brokerage project. Full-stack development in the JavaScript ecosystem (frontend & backend). Collaborate with internal and external developers in a distributed agile setup. Analyze and evaluate existing codebase, contribute to architectural decisions. Convert business requirements into technical solutions & maintain documentation. Close collaboration with team leads, business units, and stakeholders. Support onboarding-related topics (firewall, whitelisting, internal processes – client will guide this). Key Requirements: Strong experience in Java, REST API development & API design. Excellent JavaScript skills (full-stack). Proven experience as a Full-Stack Developer. Background in agile software development. Ability to analyze, structure and optimize existing code. Proactive communicator & team player. Fluent German (B2+/C1) – mandatory for documentation & daily communication. Nice to Have: Experience in regulated industries (banking, insurance, energy). IT security / firewall / networking knowledge. Experience with document management systems. Background in integration-heavy or interface-driven projects. Experience in the German financial sector.