---
title: Experiments via OpenTelemetry
description: Group OpenTelemetry traces as Langfuse experiments by attaching experiment and item attributes.
---

# Experiments via OpenTelemetry

Attach experiment metadata to [OpenTelemetry](/integrations/native/opentelemetry) spans so Langfuse groups those traces as an experiment run.

  **Using Python or TypeScript?** Use [Experiments via SDK](/docs/evaluation/experiments/experiments-via-sdk).
  The Langfuse SDKs set these attributes automatically.

See the [Experiments data model](/docs/evaluation/experiments/data-model) for how datasets, experiment runs, items, traces, and scores relate.

## Ingest experiment spans [#ingest-experiment-spans]

Set experiment and item attributes on your OTEL spans so Langfuse can synthesize them as one experiment. The attribute list, baggage propagation pattern, and per-item loop live in the OpenTelemetry integration docs:

- [Ingest experiment spans with OpenTelemetry](/integrations/native/opentelemetry/experiments)

After traces land, use the [Experiments API](/docs/api-and-data-platform/features/experiments-api) to list runs and fetch items.

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## Agent Instructions

This page is part of the [Langfuse](https://langfuse.com) documentation, published as plain Markdown for AI agents. Every page is available as Markdown by appending `.md` to its URL, or by sending an `Accept: text/markdown` header. This page: `https://langfuse.com/docs/evaluation/experiments/experiments-via-opentelemetry.md`.

### Querying these docs

If the answer is not on this page, query the documentation instead of guessing:

- **Semantic search** across all Langfuse docs, returning an answer with the relevant pages and excerpts. Ask a specific, self-contained question:

  ```bash
  curl -sG "https://langfuse.com/api/search-docs" --data-urlencode "query=How do I trace a LangGraph agent?"
  ```

- **Index of every page**: <https://langfuse.com/llms.txt>, with per-section indexes [llms-docs.txt](https://langfuse.com/llms-docs.txt), [llms-integrations.txt](https://langfuse.com/llms-integrations.txt), and [llms-self-hosting.txt](https://langfuse.com/llms-self-hosting.txt).

### Before writing Langfuse code

- **Install the [Langfuse Agent Skill](https://langfuse.com/docs/api-and-data-platform/features/agent-skill).** It encodes Langfuse's own best practices for instrumentation, prompt management, and evaluation, and materially improves results.
- **Read [What does a good trace look like?](https://langfuse.com/docs/observability/best-practices.md)** before instrumenting an application.
- **Verify endpoints, parameters, and response fields** against the [API reference](https://api.reference.langfuse.com) instead of inferring them from code examples.
- **Use the [Langfuse CLI](https://langfuse.com/docs/api-and-data-platform/features/cli)** (`npx langfuse-cli api <resource> <action>`) to read or write traces, prompts, datasets, and scores from the terminal.

Found an error in these docs? Please open an issue at <https://github.com/langfuse/langfuse-docs/issues>.