OpenTelemetry is an open-source tool used for adding observability to applications, providing logs, metrics, and traces about system behavior. It's technology-agnostic, allowing integration with any language, framework, or technology. To use OpenTelemetry with JavaScript, developers can follow a step-by-step process, including installing required dependencies, configuring the SDK, and exporting telemetry data to the console. The tool supports both push and pull models for collecting and processing telemetry data, providing flexibility for organizations to choose their strategy. With its large community of contributors, terrific documentation, and support from the Cloud Native Computing Foundation, OpenTelemetry is ready for production use, but requires rigorous testing and validation to ensure accurate data collection and processing.