What is OpenTelemetry and why has it become the industry standard?

OpenTelemetry (OTel) is a vendor-neutral, open-source observability framework that provides APIs, SDKs, and a collector for generating, collecting, and exporting telemetry data — metrics, logs, and traces — from applications. It was formed in 2019 by merging OpenCensus (Google) and OpenTracing (CNCF), and is now a CNCF incubating project with the broadest vendor support of any observability standard.

The key reason for its adoption is vendor neutrality. Before OTel, switching from Jaeger to Datadog required re-instrumenting every service. With OTel, you instrument once using the OTel SDK, export over the OTLP (OpenTelemetry Protocol) wire format, and change only the exporter configuration when switching backends. Every major observability vendor — Datadog, Honeycomb, New Relic, Grafana, AWS — accepts OTLP today.

OTel's architecture has three layers: the API (interface your application code calls), the SDK (the implementation with sampling, batching, and export logic), and the Collector (an agent/gateway that receives, processes, and re-exports telemetry). The Collector enables pipeline transforms — tail-based sampling, attribute filtering, routing to multiple backends — without touching application code.

Auto-instrumentation agents (Java agent, Python auto-instrumentation) can add traces to many frameworks with zero code changes, making adoption practical even for large legacy codebases.