Title: Senior Backend Engineer (Go/Java) - Global Fintech ContractLocation: Central London (Hybrid, 3 days in-office)Engagement: Contract with potential to convert to permanentRate: CompetitiveThe Role: You will join a critical API team responsible for high-throughput backend services and real-time payment routing decisions. This is foundational infrastructure where your work directly affects payment acceptance rates for some of the fastest-moving brands globally. You will own complex problems end-to-end from day one.What You Will Bring:Demonstrable seniority as a backend engineer owning complex services in production.Production-level expertise in Go and/or Java.Experience building or maintaining high-volume, low-latency distributed systems.Strong API design skills.Hands-on experience with AWS cloud-native deployment.A systems-thinking approach to performance, correctness, and failure modes under load.Background in payments, fintech, or financial services is highly advantageous.How to applyThis role is being filled exclusively through Randstad Digital. To be considered, please send your CV to Yogeshwari . com along with a brief note on your experience with Go/Java and high-volume distributed systems. Randstad Technologies is acting as an Employment Business in relation to this vacancy.