Senior Software Engineer (Identity)

Halcyon Labs 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 Halcyon Labs can accelerate your career so you can shape the future. Senior Engineer (Identity Team) London Office - Hybrid: 4 days in the office, 1 day working from home Halcyon Labs is seeking exceptional and highly motivated software engineers to join our engineering division in London. This is an opportunity to make a significant impact within a leading FinTech firm. As a Senior Software Engineer, you will be an integral part of our Identity team from your first day, contributing to mission-critical projects. As a Senior Engineer, you will have significant responsibility, agency, and ownership of large, mission-critical services, products, and platforms. We are committed to identifying and nurturing future technical leaders, for those who demonstrate exceptional performance and aptitude, we offer an accelerated path for career progression. What We Offer Competitive salary, performance-based bonus, and a comprehensive benefits package. A structured career development path with dedicated mentorship from senior engineers and clear opportunities for advancement. The opportunity to work on complex, intellectually stimulating projects that have a significant and measurable business impact. A dynamic, inclusive, and high-performance work environment within a leading, high-growth global FinTech company. The opportunity to build and contribute to critical projects from day one. Key Responsibilities Design, develop, test, and deploy high-quality, scalable software solutions for our global financial platform. Collaborate effectively with cross-functional teams, including product managers, designers, and other engineers, to deliver robust features and products. Participate in the full software development lifecycle, from initial ideation and technical design to deployment and operational maintenance. Contribute to technical discussions and architectural design reviews, helping to shape the future of our technology stack. Uphold and enhance engineering best practices through rigorous code reviews, automated testing, and adherence to continuous integration/deployment (CI/CD) principles. We encourage you to leverage the latest AI tools to augment your skills and accelerate your learning. We champion their responsible use, emphasizing that you must be able to fully understand and own any code or solution you develop. Required Qualifications A Bachelor's or Master's degree in Computer Science, Software Engineering, or a closely related technical discipline, with a strong academic record. You’ll probably have over 7 years of experience as a software engineer writing production-grade code, but competency, attitude, and ability matter more to us than a number. Experience working in fintech or within the financial services industry. Proficient understanding of core computer science principles, including data structures, algorithms, software design, and complexity analysis. Demonstrable programming ability in at least one modern language (e.g., Python, Java, Go, etc). Strong analytical and problem-solving skills, with the ability to approach complex challenges in a structured manner. Excellent communication and interpersonal skills, with a commitment to working effectively within a collaborative team environment. Desirable Attributes Experience building enterprise-level Identity, Access Management (IAM) platforms, Fine-Grained Access Control (FGAC) systems, and defining authorization policies. Knowledge of advanced authentication techniques, such as device binding/attestation, and experience in consolidating fragmented user identities into a unified identity model. Familiarity with cloud computing platforms (e.g., AWS, GCP, Azure) and containerisation technologies (e.g., Docker, Kubernetes). Contributions to open-source projects or a personal portfolio demonstrating technical curiosity and skill. Experience with Domain-Driven Design (DDD) and standardizing communication patterns in a centralized architecture. #LI-AT1 About us Halcyon Labs 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, Halcyon Labs has always been a fast-growing leader in fintech. Today, we bring together 2000+ 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 Halcyon Labs 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 Halcyon Labs, you can be whoever you want to be and still feel a sense of belonging no matter your story.