Worked on backend enhancements for the wazuh/wazuh-indexer and opensearch-project/OpenSearch repositories, focusing on reliability and observability. Delivered a circuit breaker memory protection feature for gRPC bulk and search operations, integrating it into core services to prevent out-of-memory errors and improve workload scalability. In OpenSearch, implemented an immutable telemetry tags design using sorted parallel arrays and factory methods, ensuring thread safety and backward compatibility. Added node-level OpenTelemetry metrics for JVM memory, garbage collection, threads, and CPU usage, optimizing performance monitoring. Emphasized Java, concurrency, and unit testing throughout, with careful attention to code quality, maintainability, and robust test coverage.