Senior Software Engineer – Backend Platform

Employment: Full-time Experience level: Mid-Senior Level Job Description What You’ll Work With You will work with a backend stack centred around: Java Spring Boot Kafka PostgreSQL Kubernetes What You’ll Do Build and evolve backend services and platform components using Java and Spring Boot Design APIs, data models, transaction flows, internal tools, and product-facing systems Design and build Kafka-based event-driven services and high-throughput transaction flows Design event flows with careful attention to ordering, idempotency, retries, failure handling, and data consistency Build systems using PostgreSQL where performance, correctness, and data integrity matter Deploy and operate backend services in Kubernetes-based production environments Drive technical decisions around consistency, latency, scalability, reliability, and security Make informed trade-offs between correctness, performance, complexity, and long-term maintainability Identify bottlenecks and continuously improve throughput, latency, observability, and system quality Own critical systems end-to-end, from design and implementation to production behaviour Strengthen engineering quality through code reviews, design discussions, and knowledge sharing Qualifications Who You Are You have strong computer science fundamentals You have substantial experience building reliable, observable, high-performance backend systems You are comfortable working with distributed systems, databases, and production services You can reason clearly about correctness, concurrency, failure modes, performance, and system design You understand scalability beyond infrastructure alone, including data modelling, consistency, caching, and concurrency control You are comfortable making architectural decisions with long-term consequences You take ownership of problems and drive them to reliable outcomes You want to work in a small team with high standards and direct technical feedback What Will Strengthen Your Application Strong professional experience with Java and Spring Boot Strong experience with Kafka or similar event-streaming/message-driven systems Experience designing event flows with careful attention to ordering, idempotency, retries, failure handling, and data consistency Strong understanding of PostgreSQL, relational database design, transactions, indexing, and query performance Strong experience deploying, operating, or troubleshooting backend services in Kubernetes-based production environments Experience designing backend systems for high-throughput, low-latency, business-critical workloads Experience with distributed systems design, especially around consistency, partitioning, concurrency, and failure handling Experience with transactional data modelling and correctness guarantees in financial, gaming, trading, payments, or other high-integrity domains Experience with production observability, including metrics, tracing, structured logging, alerting, and performance analysis Security-minded engineering, including authentication, authorisation, secrets handling, secure service communication, and defensive design Clear communication and the ability to discuss technical trade-offs thoughtfully Bonus Experience Payments, fintech, gaming, trading, or other real-money transaction domains Multi-region system design with low-latency routing and strong data integrity guarantees Caching and data-access strategies under strict correctness constraints Infrastructure as code and automated delivery pipelines Load testing, capacity planning, and performance regression prevention Incident response and production reliability ownership This Role Is Likely Not for You If You prefer clearly scoped implementation tasks over owning technical direction You are uncomfortable making decisions with architectural or long-term design impact Your experience with backend systems at scale is limited or surface-level You tend to treat performance, scalability, reliability, or security as secondary concerns rather than core design constraints Additional Information We’re building something new within Evolution. This is not an iteration on an existing product or a role focused on maintaining established systems. It is a chance to help define a new platform from first principles, using modern backend technologies to solve hard engineering problems under real production constraints. The system we’re building will operate across regions and process thousands of real-money transactions per second with strict consistency guarantees. Low latency, correctness, performance, and security are not goals we optimise for later. They are design constraints from day one. We are looking for senior engineers who want to work close to the core of the platform: backend services, event-driven systems, databases, production infrastructure, and performance-critical product flows.   Our benefits are Competitive pension, health and medical insurance 30 paid vacation days Fitness benefit (Friskvårdsbidrag) Professional growth Sport activities, parties, team buildings This is a 100% on-site position.  Based in Stockholm, Sweden.  Company Description We’re building something new within Evolution. This is not an iteration on an existing product or a role focused on maintaining established systems. It is a chance to help define a new platform from first principles, using modern backend technologies to solve hard engineering problems under real production constraints. The system we’re building will operate across regions and process thousands of real-money transactions per second with strict consistency guarantees. Low latency, correctness, performance, and security are not goals we optimise for later. They are design constraints from day one. We are looking for senior engineers who want to work close to the core of the platform: backend services, event-driven systems, databases, production infrastructure, and performance-critical product flows.