Java/Kotlin Developer | Hybrid, London | Inside IR35

Role: Java/Kotlin Developer (Backend Mobile) Location: Hybrid, City of London, 3 days per week Contract: 12-month contract Industry: Financial Services IR35 determination: Inside Rate: up to £400 per day Responsibilities Design, develop, and maintain the mobile service layer (Backend-for-Frontend) supporting large-scale mobile applications Deliver secure, reliable, and high-performing Server Side APIs for Real Time consumer experiences Write clean, maintainable code and contribute to code reviews, refactoring, and continuous improvement initiatives Collaborate with mobile, product, and design teams to define solutions that enhance usability and functionality Troubleshoot and optimize application performance for responsiveness and scalability Create robust unit tests and integration tests to ensure software reliability Manage asynchronous processing, error handling, and performance optimization in distributed systems Support Legacy system integrations and modernize existing codebases when required Follow CI/CD best practices and contribute to team development pipelines and build systems Actively share ideas, propose improvements, and participate in solution design discussions Requirements (Must Have Skills) Proven experience building Server Side applications with strong understanding of modern Back End development practices Proficiency in Kotlin or related JVM languages (Java, Scala, etc.) Practical knowledge of RESTful and GraphQL (GQL) API design and integration Hands-on ..... full job details .....