Senior Backend Engineer

This role is for engineers who want to shape core technical decisions in a small, high-caliber team. We optimize for talent density, clear thinking, and execution speed, not headcount. 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 optimize for later. They are design constraints from day one.

• Define and evolve the backend technology stack based on system constraints, trade-offs, and long-term maintainability
• Drive architectural decisions across backend services, infrastructure, and the data layer
• Design and build systems where correctness, security, and performance are non-negotiable
• Architect APIs and services for high concurrency and large volumes of real-money transactions
• Design data models and transaction flows with strong guarantees around consistency and integrity
• Make informed trade-offs between latency, consistency, and scalability in distributed systems
• Identify bottlenecks early and continuously improve throughput, latency, and reliability
• Own critical systems end-to-end, from design and implementation to behavior in production
• Collaborate with experienced engineers to challenge assumptions, refine designs, and raise the technical bar
• Strengthen engineering quality through code reviews, design discussions, and knowledge sharing

• Strong computer science fundamentals and substantial experience building reliable, observable, high-performance backend systems (required)
• Experience designing and operating high-volume distributed systems (required)
• Understanding of data integrity, concurrency, failure modes, and long-term maintainability (required)
• Understanding of scalability beyond infrastructure, including data modeling, caching, consistency, and concurrency control (required)
• Comfortable making architectural decisions with long-term consequences (required)
• Ability to take ownership of problems and drive them to a reliable outcome (required)
• Curiosity, rigor, and motivation to continuously improve both systems and engineering practices (required)
• Designing backend systems for high-throughput, low-latency, business-critical workloads (required)
• Distributed systems design, especially around consistency, partitioning, concurrency, and failure handling (required)
• Transactional data modeling and correctness guarantees in financial or otherwise high-integrity domains (required)
• API and service design for high concurrency and strict reliability requirements (required)
• Production observability, including metrics, tracing, structured logging, alerting, and performance analysis (required)
• Security-minded engineering, including authentication, authorization, secrets handling, secure service communication, and defensive design (required)
• Performance engineering across application, database, cache, and network layers (required)
• Operating services in production with strong reliability and incident ownership (required)
• Payments, fintech, gaming, trading, or other regulated or real-money transaction domains (preferred)
• Multi-region system design with low-latency routing and strong data integrity guarantees (preferred)
• Event-driven architectures, messaging systems, and idempotent workflow design (preferred)
• Postgres or other strongly consistent data stores in high-write environments (preferred)
• Caching and data-access strategies under strict correctness constraints (preferred)
• Containerized infrastructure and cloud-native operations (preferred)
• Infrastructure as code and automated delivery pipelines (preferred)
• Load testing, capacity planning, and performance regression prevention (preferred)

• Competitive salary
• Pension
• Health and medical insurance
• 30 paid vacation days
• Fitness benefit (Friskvårdsbidrag)
• Professional growth
• Sport activities, parties, team buildings