Java Developer / Software Engineer - Design & Build Fintech Product / Banking

Java Developer / Software Engineer - Design & Build Fintech Product / Banking - Spring Boot, Claude/Codex also essential. *YOU MUST HAVE BEEN INVOLVED IN DESIGN, ARCHITECTURE AND BUILD OF ANY FINTECH PRODUCT* for e.g. Current Account OR SAVINGS OR ISA's OR Fixed Term Deposits, Lending, Mortgages etc. £600-£650/DAY OUTSIDE IR35 PAY. Our Fintech Challenger Bank client based in Central London seeks a dynamic, eager to learn and technically astute Java Software Engineer who has extensive experience in Designing & Building a Payment Product *NOT PAYMENT PLATFORM* so the ideal candidate will come from for e.g. a Challenger Bank or Fintech Payment Product Company. STRONG skills in Java, Spring Boot, AI (Claude or Codex), working in a Fintech Payment domain. YOU WILL NOT BE CONSIDERED IF YOU DO NOT HAVE FINTECH & DESIGN & BUILD PAYMENT PRODUCT EXPERIENCE WITH JAVA, SPRING & STRONG AI! Our client is hiring a hands-on SENIOR Software Engineer / Java Developer to support delivery and development of Savings products within their engineering function. The emphasis is on people who can work proactively and be technically self sufficient and key skills again are Java, Spring Boot, AI Tooling, Agentic AI with some Design & Architecture. Required Experience for the Senior Software Engineer is as follows: Fintech experience, ideally start up / scale up in Fintech Product Builds (Current Account OR SAVINGS OR ISA's OR Fixed Term Deposits, Lending etc.) etcStrong hands-on Java development and coding with some design & architectureSpring Boot experienceAI Tooling & Agentic AI with good Claude or Codex skillsHighly Desirable is Development experience with ISA implementations / ISA integrations, Current Account OR SAVINGS OR Fixed Term Deposits, Lending etc. This is a 6 month initial contract with 2 days/ week on site in London and 3 days remote per week. YOU WILL NOT BE CONSIDERED IF YOU DO NOT HAVE FINTECH & PAYMENTS & JAVA & STRONG AI.