Senior Full Stack Engineer (Cards)

Cobalt Streamworks helps ambitious businesses unlock global growth, and we take the same approach with our people. We encourage innovation and movement, collaboration and problem-solving, and foster an environment where everyone can feel they belong, are valued, supported and empowered to succeed. If you’re a collaborator who wants to help transform how businesses operate globally, get in touch - we’d love to discuss how Cobalt Streamworks can accelerate your career so you can shape the future. Senior Fullstack Engineer (Business Cards) London Office - Hybrid: 4 days in the office, 1 day working from home We're looking for a Senior Fullstack Engineer to join our new, rapidly growing Cards team. In this role, you'll work on innovative fintech products, helping to solve customer problems by leveraging data and an entrepreneurial spirit. We're looking for someone who is ever-curious and passionate about continuous learning, who can identify and use the right tools for the job, regardless of language or framework. What We Offer: Competitive salary and benefits package. Opportunities for professional growth in a leading European fintech company. High ownership and visibility on a critical business initiative. A collaborative, open, and dynamic environment. The chance to shape how global businesses connect with Cobalt Streamworks. Responsibilities: Lead the design and delivery of complex features for customer-facing web applications. Experience in FinTech, banking, or another closely related sector, with a strong understanding of financial systems and building within a regulated environment. Drive frontend development using React/VueJS and backend development with Python. Collaborate with data engineers to design, build, and optimize robust data pipelines for analytics and machine learning. Own the full product lifecycle, including development, maintenance, monitoring, and alerting. Mentor junior engineers and champion technical excellence. Collaborate cross-functionally to deliver impactful solutions. Contribute to the technical roadmap, identifying opportunities for innovation. Ensure code is testable with good test coverage. Stay up-to-date with emerging technologies. This position may require being on-call at times. About You Bachelor's or Master's degree in Computer Science or equivalent experience. 5+ years of fullstack development experience, with a focus on high-performance web applications, modern frontend frameworks (React), and microservices architectures. Proficiency in Python3, REST APIs, FastAPI, or similar technologies. Strong understanding of architecture, design patterns, and building scalable, testable code (unit & integration tests). Comfortable with containerization, monitoring, and cloud infrastructure. Used to working in a fast-paced environment and a self-starter who can autonomously drive complex projects. Excellent communication and collaboration skills in English. Bonus Points: Experience with Machine Learning or Data Science projects (e.g., LLMs). Working knowledge of Terraform. Experience with event-driven architectures and event sourcing. Experience with Mobile Development, ideally in React Native. #LI-AT1 About us Cobalt Streamworks delivers sophisticated, integrated solutions — business accounts, hedging, and financing — on a single platform with a seamless workflow. Our success is built on a simple premise and singular purpose: To help businesses operate and scale globally. Since its founding in 2009, Cobalt Streamworks has always been a fast-growing leader in fintech. Today, we bring together 1,800+ Eburians across nearly 70 cities and we’re always looking to add to our team. At the heart of our offering is a proprietary platform, purpose-built to help businesses seamlessly streamline and manage global cash flow. We focus on continuous product evolution and innovation to build the infrastructure for borderless growth and help our clients scale at every stage. The opportunities at Cobalt Streamworks are as diverse as our people, ranging from business development to engineering roles across our tech pillars. We believe in inclusion. We stand against discrimination in all forms and are against the intolerance of differences that makes us a modern and successful organisation. At Cobalt Streamworks, you can be whoever you want to be and still feel a sense of belonging no matter your story.