Backend Software Engineer / Developer (Kotlin Java Spring Boot) London / WFH to £80kAre you a backend focused technologist with real-time financial systems experience?You could be progressing your career as a Backend Software Engineer at a highly successful financial software house whose award winning software enables customers to build high-performance web trading apps that deliver real-time information securely and reliably.What's in it for you:Salary to £80kPension, Income Protection, Life AssurancePrivate medical and dental careGym membershipChildcare vouchers, cycle to work scheme, season ticket loanAbility to buy extra holiday Your role:As a Backend Software Engineer you will build high-performance, real-time servers powering critical financial applications, designing fast, intuitive APIs that simplify integration. You'll focus on writing secure, well-architected and thoroughly tested systems, ensuring reliability at scale.Alongside day-to-day development, you'll have the opportunity to explore new technologies, take part in hack days and collaborate with experienced engineers in a supportive, low-ego environment where ideas are encouraged and innovation thrives.Location / WFH:You can work from home most of the time, joining colleagues in the London office once a week / fortnight. About you:You have experience within a financial services environment working on complex real-time systemsYou have commercial server side development experience using Kotlin, likely to be from a Java backgroundYou have experience with Spring Boot and microservicesYou have experience with messaging technologies such as Kafka, FIX, RSocket, ProtobufYou have strong knowledge of threading paradigms (Kotlin Coroutines would also be a plus)You have experience with automated test frameworks for testing your own codeYou have a good knowledge of SQL databasesYou have a good appreciation of AI and the pros and cons of use agentic AI development and tools such as Gemini, CLI, ClaudeYou're collaborative and pragmatic with great communication skillsApply now to find out more about this Backend Software Engineer / Developer (Kotlin Java Spring Boot) opportunity. At Client Server we believe in a diverse workplace that allows people to play to their strengths and continually learn. We're an equal opportunities employer whose people come from all walks of life and will never discriminate based on race, colour, religion, sex, gender identity or expression, sexual orientation, national origin, genetics, disability, age, or veteran status. The clients we work with share our values.JBRP1_UKTJ