Senior Backend Engineer

What You’ll Do

• 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

Who You Are

• You have strong computer science fundamentals and substantial experience building reliable, observable, high-performance backend systems
• You have experience designing and operating high-volume distributed systems
• You think in terms of data integrity, concurrency, failure modes, and long-term maintainability
• You understand scalability beyond infrastructure alone, including data modeling, caching, consistency, and concurrency control
• You are comfortable making architectural decisions with long-term consequences
• You take ownership of problems and drive them to a reliable outcome
• You are curious, rigorous, and motivated to continuously improve both systems and engineering practices

Relevant Experience

• Designing backend systems for high-throughput, low-latency, business-critical workloads
• Distributed systems design, especially around consistency, partitioning, concurrency, and failure handling
• Transactional data modeling and correctness guarantees in financial or otherwise high-integrity domains
• API and service design for high concurrency and strict reliability requirements
• Production observability, including metrics, tracing, structured logging, alerting, and performance analysis
• Security-minded engineering, including authentication, authorization, secrets handling, secure service communication, and defensive design
• Performance engineering across application, database, cache, and network layers
• Operating services in production with strong reliability and incident ownership

Bonus Experience

• Payments, fintech, gaming, trading, or other regulated or real-money transaction domains
• Multi-region system design with low-latency routing and strong data integrity guarantees
• Event-driven architectures, messaging systems, and idempotent workflow design
• Postgres or other strongly consistent data stores in high-write environments
• Caching and data-access strategies under strict correctness constraints
• Containerized infrastructure and cloud-native operations
• Infrastructure as code and automated delivery pipelines
• Load testing, capacity planning, and performance regression prevention

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, or security as secondary concerns rather than core design constraints

How To Apply

Please send:

• A short note on why this role is a strong fit for you
• Your resume or LinkedIn profile
• GitHub, portfolio, or code samples, if available
• 1-3 examples of backend systems or features you’ve built where scale, performance, security, or robustness were central, including the technical challenge, the system context, and your specific contribution

Our Benefits are

• Competitive salary, 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.