We are Billie, the leading provider of Buy Now, Pay Later (BNPL) payment methods for businesses, offering B2B companies innovative digital payment services and modern checkout solutions. We are to create a new standard for business payments and have made it our mission to simplify the purchasing experience for all businesses making it a tool for growth. Our solutions are based on proprietary, machine-learning-supported risk models, fully digitized processes and a highly scalable tech platform. This makes us a deep-tech company building financial products, not the other way around. We love building simple and elegant solutions and we strive for automation and scalability.

At Billie, we're not just building payment solutions; we're architecting the future of B2B commerce. We empower businesses to operate with unprecedented freedom and efficiency, leveraging a sophisticated, machine-learning-driven platform that streamlines financial transactions. We are a team of deep-tech innovators, driven by the challenge of transforming complex financial realities into simple, elegant, and automated experiences. If you're a JVM engineer who thrives on solving foundational problems and shaping the technical trajectory of a rapidly scaling fintech, this is your opportunity to write a significant chapter in our story.

Your Chapter at Billie: The Role

As a JVM / Kotlin Engineer, you will join the core of our engineering team within Billie's Payments domain. This domain is the beating heart of our business, covering the intricate movement of funds – from initiation and settlement to transaction identification, reconciliation, and reporting. This isn't just about writing code; it's about deeply understanding this critical business area, challenging established norms, and strategically building the next generation of our platform. You will be at the forefront of our architectural evolution, steering our transition towards a cutting-edge microservices landscape and embedding Domain-Driven Design (DDD) principles that will define our engineering culture for years to come. Your insights will directly influence system design, while your pragmatic approach will ensure the seamless modernization of our existing infrastructure, including foundational PHP components, as we continue our ambitious growth trajectory.

Crafting the Future: What You’ll Do

• Architectural Leadership: You will collaborate closely with Senior Staff Engineers to design, challenge, and refine the architecture of our high-throughput, fault-tolerant payment systems. This means taking ownership of strategic decisions that pave the way for scalable, secure, and resilient operations within the Payments domain.

• Leading the Microservices Journey: Be a key driver in our evolution from current systems to a truly decoupled microservices architecture. Your expertise in JVM (Kotlin) will be essential in conceptualizing, building, and deploying new services that facilitate, orchestrate, and monitor all money movements behind Billie's products.

• Championing Domain-Driven Design: You'll be instrumental in fostering a deep understanding and practical application of DDD across the team. This involves guiding the design of software that intimately mirrors our business domains, ensuring clarity, maintainability, and strategic alignment, particularly for core payment functionalities.

• High-Quality System Development: From ideation to deployment, you will design, develop, test, and maintain robust software solutions, primarily using JVM technologies (Kotlin), for our mission-critical payment domain, spanning topics like banking infrastructure, billing, invoicing, and automated accounting.

• Bridging the Present to the Future: You will support and enhance our existing infrastructure, including components built with PHP, facilitating a thoughtful and strategic transition path, ensuring continuity and stability during our modernization efforts within the payment ecosystem.

• Cross-Functional Collaboration: Your impact will extend beyond code. You’ll work hand-in-hand with product managers, data scientists, and other engineering teams, translating complex business needs into elegant technical solutions and delivering features that directly accelerate Billie's success by evolving our payment capabilities.

• Engineering Excellence: Drive continuous improvement in our engineering practices, contributing to the evolution of our CI/CD pipelines, advocating for fast feedback loops, and ensuring a culture of quality and automation across the Payments domain.

Your Toolkit & Experience: What You’ll Bring

• JVM Mastery (Kotlin Focus): You possess significant experience in JVM software development, with a strong emphasis on Kotlin. You've built and scaled highly available, resilient systems in production environments.

• Foundational PHP Acumen: You have a solid understanding or working knowledge of PHP, demonstrating an ability to quickly grasp and contribute to existing systems, facilitating their successful modernization.

• Architectural Vision: You're not just an implementer; you have a strong track record of contributing to and influencing architectural designs for distributed systems and microservices. You enjoy tackling complex system design challenges.

• DDD Enthusiasm: You are familiar with Domain-Driven Design principles and are passionate about applying them to create well-structured, maintainable, and business-aligned software.

• Modern Engineering Practices: You are adept at modern software development practices, including Test-Driven Development (TDD), collaborative coding (mobbing, pair programming), and continuous integration/delivery.

• Pragmatic Problem-Solver: You approach complex technical challenges with a proactive, self-driven, and pragmatic mindset, always seeking the most effective and sustainable solutions.

• Impactful Communicator: Your excellent written and verbal communication skills in English allow you to articulate intricate technical concepts clearly to diverse audiences, fostering effective collaboration.

• Your Experience: Typically, 4+ years of hands-on software engineering experience in a fast-paced, high-impact environment.

What we offer:

• Challenging and impactful work that drives personal and professional growth

• One of the best Virtual Shares Incentive Programs in the market, so that everyone at Billie is invested in our success

• Flexible work hours and trust in your ability to deliver, empowering you to take control of your work-life balance

• A hybrid working approach that allows you to work from home for up to 3 days per week

• Enjoy 30 days vacation per year on top of paid public holidays, sabbatical opportunities, and extra child sickness leave for parents.

• Our “Catch a Ride with Billie” program that enables discounted access to Berlin Public Transport (BVG), Deutschland-Ticket, OR JobRad

• A yearly development budget to broaden your skill set and horizons

• Free German group classes

• An English-speaking, multicultural team with more than 40 nationalities

• Building meaningful connections with your colleagues through company and team events, interest groups, the Billie run club, game nights, and more, powered by our Formula Fun Team!