OpenTelemetry (OTel)
Open vendor-neutral standard for telemetry data (traces, metrics, logs) across all software systems. Now the emerging standard for LLM observability too.
Last updated: April 26, 2026
Definition
OpenTelemetry is the CNCF-graduated standard for instrumenting applications. It defines a single format for emitting traces, metrics, and logs, plus SDKs for every major language. The point is portability: instrument once with OTel, and your data flows to any backend (Datadog, Honeycomb, Grafana, Langfuse) without rewriting the instrumentation. For LLM systems, the OpenLLMetry project extends OTel with semantic conventions for LLM-specific spans (model name, token counts, prompt and completion bodies).
When To Use
Default to OTel for any new instrumentation. Even if you start with one observability vendor, OTel preserves your option to switch later without rewriting code.
Related Terms
Building with OpenTelemetry (OTel)?
I've shipped this pattern in real production systems. If you want a second pair of eyes on your architecture, that's what I do.