Mid Backend Engineer

About the role

About Selina At Selina Finance , our mission is to provide exceptional value with simple and flexible financial products. We're achieving this by building a next-generation digital lender targeting homeowners across the UK. More than £2tn of equity value is locked up in UK homes, while homeowners still need to rely on high-interest-rate consumer loans, credit cards, or overdrafts. We believe this is unfair and unnecessary. We offer a financing product unlike anything else out there, one that is as flexible as a current account, as affordable as a mortgage, and as easy to apply for as a consumer loan. We are building an incredible team and culture of high performance, development, reward and recognition, ready for the next phase of our adventure, and this is where you come in! We have quite a few things to be proud of: 🌏 We have 19 different nationalities across our London + Manchester offices 🏆 Voted as 'one of the fastest-growing businesses in the UK' by Business Leader Growth 500 for 2025 🏆 Voted top 30 of 'Tempos 100 best start-ups to work for 2023' 🦾 Disability Confident Committed employer 🏆 BCorp Certified ✏️ Rated highly in our employee survey on: ✔ Workplace Culture ✔ Work Life/Balance ✔ Employee Recognition Purpose of the Role We're disrupting the antiquated, paper-based mortgage market by delivering better products and a superior customer experience. In your role, you will: Help design, shape and deliver a leading FinTech product and engineering team Contribute to the team's work with high-quality, well-tested and scalable code Develop high-class back-end code in a microservice architecture that builds the foundation of all Selina's tech products Support the development of the software stack (e.g. code reviews, unit tests, CI) and documentation Work closely with our team to understand our customers' needs You'll be right in the heart of the action here at Selina. We're looking for driven, detail-oriented team players. We win by placing customers' interests first! Requirements About You Strong knowledge of Java Core, including collections, generics, streams, concurrency basics, and modern Java features. Good understanding of object-oriented design principles and clean code practices. Commercial experience with Spring Boot and the Spring ecosystem Experience building REST APIs, including an understanding of HTTP fundamentals Experience with service-to-service communication and event-driven architecture, including messaging/streaming with Apache Kafka Experience with unit and integration testing using tools such as JUnit and Mockito (Testcontainers or WireMock is a plus). Understanding of web application security basics, including authentication, authorization, and OAuth 2.0 concepts. Experience working with MongoDB or other NoSQL databases, including basic data modelling and indexing. Experience with Git and standard collaborative workflows (pull requests, code reviews, resolving conflicts). Ability to work independently on tasks, collaborate in a team, and deliver features from design to production. Nice to have/Bonus points Experience with Kotlin for backend development. Experience with Keycloak or other Identity and Access Management solutions. Experience with observability tools such as Grafana, Loki, Prometheus, and logging/monitoring systems. Experience with Docker and Kubernetes. Experience with Python and FastAPI for building backend services. What we offer: £70,000-£80,000 base salary 25 days' annual leave, plus bank holidays 30 days' work-from-anywhere allowance Bi-annual Bonus (discretionary) Volunteering allowance Growth Shares Annual L&D budget Cycle to work scheme 3% pension contribution Monthly socials Free access to mental health support via 'Spill' A choice of benefits that work for you, courtesy of our benefits platform, 'Thanks Ben' Annual £60 cycle allowance for Santander cycles or Evans (via 'Thanks Ben') Workplace Nursery Benefit, allowing eligible nursery costs to be paid via salary sacrifice Our Values Our values underpin how we work together as a high-performing team, driving our growth and success. ✅Take Ownership - We all act as owners. We make decisions in the best interest of the company. We pride ourselves on solving problems, not finding barriers. We have a bias for action; we move fast and we deliver. 🥇Customer Obsessed - We all act as owners. We make decisions in the best interest of the company. We pride ourselves on solving problems, not finding barriers. We have a bias for action; we move fast and we deliver. 🚀Drive Change - We all act as owners. We make decisions in the best interest of the company. We pride ourselves on solving problems, not finding barriers. We have a bias for action; we move fast and we deliver. 💪Empower Our Team - We believe that collaboration and teamwork are the cornerstones of success and we set up our team for great achievements We are an equal opportunities employer and are committed to ensuring that no applicant or employee r