Senior Software Engineer - Java (m/f/x)

About Whitebox

Whitebox is one of the leading digital wealth managers in Germany. We are a rapidly growing company with flat hierarchies, short decision-making processes, and a strong emphasis on personal responsibility among our employees. Our globally distributed and highly qualified software engineering team is dedicated to revolutionizing the financial markets.

Joining this team will place you at the forefront of fintech innovation. You will have the opportunity to scale a top-tier product, ultimately driving significant value for the business. Most importantly, your work will help shape the future of the financial services landscape.

About the Role

We are a European fintech company seeking a highly skilled Software Engineer (Java) to architect, build, and scale our core financial systems. You will operate at the intersection of complex financial concepts and high-performance software engineering, focusing on brokerage operations and robo-advisory platforms. We are looking for an engineer who treats code as craft, communicates flawlessly across remote environments, and pragmatically leverages modern AI tools to ship robust, tested software faster.

Key Responsibilities

• Design and maintain high-throughput, fault-tolerant backend services powering our brokerage and robo-trading engines.
• Write exceptionally clean, highly concurrent, and well-tested code primarily in Java.
• Champion Test-Driven Development (TDD) and Behavior-Driven Development (BDD) to ensure the absolute reliability required in financial software.
• Handle complex state management and ensure data integrity across our architecture.
• Containerize applications and ensure smooth local and deployment workflows using Docker.
• Collaborate asynchronously and synchronously in a fully remote, Agile environment.
• Act as a multiplier for your team by integrating AI coding assistants into your workflow for boilerplate, test generation, and refactoring, while maintaining strict architectural oversight (no "vibe coding"). Knowledge on Spec-Driven Development tools is a plus.

Requirements

Deep Technical Expertise

• Extensive, production-level experience with Java and the JVM ecosystem. You know how to leverage Java for strict performance, concurrency, and reliability.

Security First

• Dealing with financial data requires a paranoid approach to security. Proven experience with secure coding practices, data encryption, OWASP principles, and secure API design is mandatory.

Testing Champion

• Deep commitment to TDD and BDD. You believe untested code is legacy code, especially when dealing with client funds.

Distributed Systems Transactions

• Strong understanding of managing state and ensuring data consistency across distributed systems (e.g., handling complex financial transactions, preventing double-spending, and managing race conditions).

Pragmatic AI Integration

• Proven experience using AI tools as a powerful pair-programmer to multiply productivity and test coverage.

Remote & Agile Native

• Strong track record of thriving in distributed, agile teams.

Impeccable Communication

• You can explain technical decisions to non-technical stakeholders and write clear documentation.

Infrastructure

• Solid experience with Docker and containerized environments.

Domain Knowledge

• Demonstrable understanding of financial markets, brokerage mechanics, and automated/robo-trading concepts.

Nice to have

Ruby on Rails Knowledge

• Experience with Rails to help maintain, interface with, or migrate existing business logic services.

Rust

• Familiarity with Rust (valuable for ultra-low latency execution components).

European Regulations

• Understanding of European financial compliance and regulatory frameworks (e.g., MiFID II).

FIX Protocol

• Experience with the Financial Information eXchange (FIX) protocol for order routing.

Kubernetes (K8s)

• Experience working with Kubernetes orchestration.

CI/CD

• Familiarity with deploying code through established Continuous Integration/Continuous Deployment pipelines.

At a glance

• Job overview
• Location Remote
• Experience Required +7 years
• Contract Type Contract
• Employment Type Full-time
• Team Software Engineering
• Team Size 20+

Your first week

• meet with the team and have One-on-One conversations with everyone,
• become introduced to our business and upcoming challenges, and
• discuss the current objectives with our leadership team.

Your first month

• work out all the particular areas of the codebase and functionality,
• elaborate on how all the pieces fit together, and
• explore how it…