EXIST Funding

This role is open to Master's and PhD students or recent graduates (within 5 years) from German universities, eligible for EXIST Gründerstipendium funding.

Location

Remote within Germany. Open to students at any German university eligible for EXIST Gründerstipendium.

Role Overview

You will join the core engineering team as a founding engineer. You will own the backend payment engine end to end: transaction flows, wallet management, SEPA Instant settlement, KYB/KYC integration, recurring mandates, refund logic, and the compliance export layer (DATEV, Kassenbuch, GoBD, fiskaltrust). On mobile, you will contribute to the React Native consumer and merchant apps alongside our mobile engineer.

You will own what you build from development through deployment, monitoring, and production reliability. The architecture decisions you make in the first six months will run in production for years.

What you will do

• Design and build the backend payment engine: transaction flows, wallet management, SEPA Instant settlement, offline payment authorization, and recurring mandate billing.
• Own KYB/KYC integration and the compliance export layer: DATEV, Kassenbuch, GoBD, and fiskaltrust for KassenSichV.
• Build REST APIs for financial-grade reliability and high-throughput transaction processing, including full R-transaction handling and reconciliation pipelines.
• Contribute to the React Native consumer and merchant mobile apps alongside our mobile engineer.
• Own the full lifecycle of what you build, from development through deployment, monitoring, and continuous improvement.
• Integrate AI tooling into your development workflow as a matter of course: code generation, automated testing, and intelligent review.

Who you are

• Currently enrolled in a Master's or PhD program at a German university, or recently graduated within the last 5 years.
• Solid backend engineering foundation — you've built systems that handle real data, you understand databases, APIs, and what happens when things fail.
• You think carefully about data consistency and reliability. You've had to ask yourself, "what happens if this fails halfway through?" and actually worked out the answer.
• Some exposure to financial systems, transactions, or data integrity is a plus — but curiosity and the ability to learn fast matter more than a specific background.
• You take ownership of what you build end-to-end, from writing the code to making sure it runs in production.
• You can explain technical decisions clearly to people who aren't engineers.
• Comfortable with ambiguity and early-stage risk. There is no playbook yet. You will help write it.
• Our stack includes Go, Node.js, Python, React Native, PostgreSQL, and REST APIs over SEPA Instant rails. Experience with any of these is a plus — what matters more is that you pick up new tools fast and care about writing reliable, maintainable code.