Senior Backend Engineer — Go & Java · Distributed systems, cloud-native
15+ years in production backend development, the last five on Go with Java/Spring Boot alongside it. I build high-load distributed systems: event-driven architectures on Kafka, gRPC services, and stateful workloads on Kubernetes. Currently own core services of a loyalty platform serving 10M+ active users at thousands of TPS, running at 99.99% availability.
Hands-on by choice — I write production code daily and own services end to end: data model, API design, rollout, on-call.
Remote-first, based in Spain (CET). EU work authorization, no sponsorship required — employment via a Spanish entity or EOR, or B2B contract.
Looking for senior individual-contributor backend roles. Not looking for a people-management track.
Languages — Go, Java / Spring Boot · Python (tooling, automation) · Rust, C (internal tools)
Infrastructure — Kubernetes (Operator SDK, CRDs, client-go), Docker, AWS, Linux, Nginx, Jenkins, GitHub Actions
Data & messaging — Apache Kafka, PostgreSQL, ClickHouse, Redis, Elasticsearch, Apache Ignite
Observability — Prometheus, Grafana, OpenTelemetry
Practices — Microservices, event-driven design, CQRS, DDD, REST and gRPC / Protobuf APIs, high availability & disaster recovery, on-call ownership
Both are live, self-hosted and built end to end — backend, deployment and everything in between.
Yes: it is a canvas for drawing boxes and arrows. The difference is what happens when you press Check. Claude reads the design against the requirements of the task — a vendor that answers in three to seven minutes, two hundred seats and five thousand buyers — scores it on five axes, and pins what is missing to the components it is missing from. Every box the requirements never asked for costs you.
Practise algorithm problems by assembling logic out of blocks instead of writing code. Ten primitives cover the shape of most interview problems; the diagram lays itself out top to bottom, and branches merge back into the flow automatically.
A language-learning app built around exploring the world rather than drilling lists. Point the camera at something and it names the objects in the picture as new vocabulary. Beyond that: role-play dialogues with your own scenario and written corrections, a two-player word-guessing mode, counting practice and themed vocabulary sets.
- A custom Kubernetes predictive auto-scaling controller (Go, Operator SDK) that reads leading metrics to pre-warm heavy JVM services ahead of traffic spikes, eliminating cold-start failures during peak campaigns.
- A greenfield suite of distributed Go and Java microservices replacing a legacy monolith, with Kafka event-driven communication and strict consistency guarantees across service boundaries.
- The real-time Kanban backend at Bitrix24: concurrent board updates, conflict resolution and live sync across multiple simultaneous clients.
Most of my production work lives in private repositories.