About the Role
La descripción completa del puesto cubre todas las habilidades asociadas, la experiencia previa y cualquier cualificación que se espera que tengan los solicitantes.
We're looking for a Principal Server Engineer to own the backend systems powering our live games - services currently supporting 1M+ DAU. You'll be responsible for performance, scalability, and reliability at the core of our infrastructure, working closely with the engineering team on everything from schema design to incident response.Experience: 8+ years
Nice to Have
CI/CD and DevOps experience (GitHub Actions, GitLab CI) plus monitoring/alerting (Prometheus, Datadog)
Strong grasp of networking protocols — WebSockets, gRPC/HTTP2, UDP/TCP tuning for low-latency real-time systems
Requirements
Responsibilities
Design, build, and maintain Go/Python backend services for live, high-traffic game titles
Own database schema design and query performance across PostgreSQL systems
Drive horizontal scaling strategy - optimizing CPU/memory footprint and reducing lock contention over vertical scaling
Profile and resolve memory leaks, CPU spikes, and deadlocks in production
Lead root-cause investigations for performance issues and outages, from detection through resolution
Architect and maintain in-memory caching/state layers (Redis/KeyDB/Memcached)
Design and run load tests to surface breaking points ahead of release
Requirements
Crucial
Deep Go & Python expertise — language internals, execution models,



and performance tuning (goroutine management, GC tuning, zero-allocation techniques)
Strong PostgreSQL fluency — scalable schema design, query plan analysis, index strategy optimization, with real examples of resolving bottlenecks via data layout or query architecture changes
Proven experience scaling systems supporting 350k+ DAU, with a horizontal-scaling-first philosophy (efficient serialization/deserialization via Protobuf/MsgPack, reduced lock contention)
Hands-on profiling experience — identifying and resolving memory leaks, CPU spikes, and deadlocks
At least 2 concrete examples of complex production performance issues or outages, including root cause analysis and resolution methodology
At least 2 released production projects as xhfqzwm a core backend engineer handling live traffic
Important
Hands-on experience with Redis, KeyDB, or Memcached — caching, rate-limiting, state management, including cache stampede mitigation, serialization overhead, and eviction policy design
Solid TDD/BDD judgment and practical load-testing experience (e.G., Artillery)
Practical experience with the Nakama framework — custom Go/Lua modules, matchmakers, storage engine, real-time multiplayer sockets
Practical GCP/Google App Engine experience — deploying, monitoring, and scaling serverless/container services
Benefits
Market competitive, tax-free USD salaries
Paid Time Off
Annual Performance Reviews
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📌 Principal Server Engineer (Madrid)
🏢 UserWise Services
📍 Madrid