Full-Stack API Developer

Quick Facts

• 100% remote

• Languages: German + English

• Start: ASAP (within 2 weeks)

• Engagement: B2B, up to 45 EUR/h

• Duration: contract until end of year; extensions likely in 6–12 month increments

• Onboarding: 1 week on-site in Hanover

• Additional visits: once every 2–3 months for 3 days on demand

• Workload: full-time (40 hours/week)

• Industry: Finance

Description

The Full-Stack API Developer integrates REST API interfaces into existing systems and enhances solutions in a large-scale finance integration and brokerage project. You will perform full-stack development in the JavaScript ecosystem (frontend & backend), collaborate with a distributed agile team, and help shape architectural decisions by analyzing the current codebase. The role also involves translating business requirements into technical solutions and maintaining documentation.

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 the 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 provides guidance)

Requirements

• Strong experience in Java, REST API development, and 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

Benefits

• Fully remote work with periodic on-site onboarding and possible short visits

• B2B engagement (up to 45 EUR/h) with an initial term until year-end and expected extensions

• Finance industry experience within a distributed agile team