Senior Software Engineer - Ruby on Rails

We are a European fintech company seeking a highly skilled Software Engineer (Ruby on Rails) 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., * Design and maintain highly reliable backend services powering our brokerage and robo-trading engines.

• Write exceptionally clean, well-tested code primarily in Ruby on Rails, managing complex financial logic and business rules.

• 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., The first week concerns context: our organization's why, what, and how. The first week is always exciting and challenging, and we want you to know the team and gain confidence that we will always have your back. You will

• 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

The first month is for orientation. You will get to know the codebase, understand the reasons behind past design decisions, and understand our organization's context. In detail, you will

• work out all the particular areas of the codebase and functionality,
• elaborate on how all the pieces fit together, and
• explore how it relates to the product and value we provide our customers.

Your first quarter

In the first quarter, you will become fully integrated into your team and be able to work with everybody on our ongoing projects. In line with this, you will also incorporate yourself into your chapter. You will

• start bringing value to our customers,
• moving our projects forward, step by step,
• working towards your own goals raising the bar, and
• participating in engineering team meetings, defining our principles, goals, and how we want to work.

Do you have experience in Rust (programming language)?, Are you passionate about creating innovation? Do you enjoy developing groundbreaking digital products that utilize cutting-edge technologies? Are you excited about driving growth in digital wealth management and delivering a unique customer experience? If so, we would love to hear from you!, * Deep Technical Expertise: Extensive, production-level experience with Ruby on Rails. You deeply understand the framework and how to optimize it for scale and maintainability.

• 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

• Java Knowledge: Experience with Java to help interface with or transition specific high-performance 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.

• This position is a permanent, full-time (40h/wk) role.

• Thirty days of paid vacation.

• 100% remote.

• Attractive remuneration package and free choice of hardware.

• Weekly manager one-on-ones, flat hierarchies, and an open-door mentality.

We are Whitebox, and we believe investing can be fun, simple, and low-risk. Whitebox has started to make digital wealth management accessible to everyone and tailored to individual needs while keeping asset management simple, transparent, and inexpensive. 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.