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Overview
Job details
Fully remote
Per the ad.
Requirements
Have the right to work in Spain
UserWise Services doesn't mention sponsorship in the ad.
Work in English
English is required, per the ad.
Have 8+ years of experience
Senior-level role.
Pay & benefits
What you'll get
- Market competitive, tax-free USD salaries
- Paid Time Off
- Annual Performance Reviews
Requirements
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
The role
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
What you'll do
- 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 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
About UserWise Services
UserWise Services is a technology services company specializing in mobile gaming, offering expertise in game development, product management, and data analytics. The company operates globally, with a focus on supporting game studios in optimizing their live operations and player experiences. Their team works across engineering, product, and data disciplines to deliver high-impact solutions for the gaming industry.
Based in Barcelona, Spain, UserWise Services has established a presence in one of Europe's key tech and gaming hubs. The company's work culture emphasizes collaboration and innovation, making it an attractive option for international professionals looking to contribute to the mobile gaming sector. With roles spanning product management, engineering, and data analysis, UserWise offers opportunities for skilled individuals to work on live game evolution and player-centric projects in a dynamic, multicultural environment.
- Employees
- 40
- Headquarters
- Barcelona, Spain
- In Spain
- Barcelona
- Website
- userwise.io
Good to know if you are moving
- Based in Barcelona, a major European tech and gaming hub, offering a vibrant lifestyle and strong professional network.
- Focus on mobile gaming provides opportunities to work on live game operations and player engagement projects.
- Roles include product management, engineering, and data analytics, suitable for specialists in the gaming industry.
- International team environment likely, given the global nature of the gaming sector and Barcelona's diverse workforce.



