At Fitel.io, I build and maintain Go backend services for a CRM system, including REST and gRPC APIs, offline synchronization, and background processes.
I've implemented optimistic locking, versioning, and idempotency to prevent data loss and duplicate operations. I also built conflict detection and resolution for concurrent editing.
I improve external API reliability through timeouts, exponential-backoff retries with jitter, circuit breakers, and concurrency limits. I use Redis caching and pprof to strengthen resilience and diagnose memory and performance issues.
Previously, as a freelance JavaScript developer, I delivered backend APIs, business logic, database operations, third-party integrations, and Docker-based development and deployment environments.
