# Observability for LangServe with Opik

[LangServe](https://github.com/langchain-ai/langserve) does not define its own standalone OpenTelemetry bootstrap. Instrumentation is configured at the host app/runtime layer (typically FastAPI + LangChain components).

## When this guide applies

Use this when your LangServe routes run inside a Python web app and you want request + framework spans in Opik.

## Opik OTLP endpoint modes

For full endpoint/header details, see [Opik OpenTelemetry overview](/guides/multi-language-opentelemetry).

::::tabs
:::tab{title="Opik Cloud"}
```bash wordWrap
export OTEL_EXPORTER_OTLP_ENDPOINT=https://www.comet.com/opik/api/v1/private/otel
export OTEL_EXPORTER_OTLP_HEADERS='Authorization=<your-api-key>,Comet-Workspace=<your-workspace>,projectName=<your-project-name>'
```

Required headers: `Authorization`, `Comet-Workspace`
Optional headers: `projectName`
:::

:::tab{title="Enterprise deployment"}
```bash wordWrap
export OTEL_EXPORTER_OTLP_ENDPOINT=https://<comet-deployment-url>/opik/api/v1/private/otel
export OTEL_EXPORTER_OTLP_HEADERS='Authorization=<your-api-key>,Comet-Workspace=<your-workspace>,projectName=<your-project-name>'
```

Required headers: `Authorization`, `Comet-Workspace`
Optional headers: `projectName`
:::

:::tab{title="Self-hosted instance"}
```bash wordWrap
export OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:5173/api/v1/private/otel
export OTEL_EXPORTER_OTLP_HEADERS='projectName=<your-project-name>'
```

Required headers: none by default
Optional headers: `projectName`, auth headers if enabled
:::
::::

## OTEL configuration pattern for LangServe

Intent:
Configure telemetry at the LangServe host boundary so request and framework spans can be exported.

Applies when:
LangServe is mounted in an app you control (for example FastAPI).

Required inputs:

- host runtime instrumentation enabled
- OTLP endpoint
- OTLP headers for your deployment mode

Optional inputs:

- explicit `service.name`
- additional framework or library instrumentors
- route-level filtering/sampling

Minimal valid setup:

- set `OTEL_EXPORTER_OTLP_ENDPOINT`
- set `OTEL_EXPORTER_OTLP_HEADERS`
- enable instrumentation for your host app and LangChain stack

Use canonical host/runtime setup from:

- [OpenTelemetry FastAPI instrumentation](https://opentelemetry-python-contrib.readthedocs.io/en/latest/instrumentation/fastapi/fastapi.html)
- [Opik LangChain integration guide](https://www.comet.com/tracing/integrations/langchain)

## Validation

1. Send a request through a LangServe endpoint.
2. Confirm a root HTTP/server span is emitted from your host app.
3. Confirm downstream LangChain/LangServe-related spans are exported and visible in Opik.

## Source references

- [LangServe repository](https://github.com/langchain-ai/langserve)
- [OpenTelemetry FastAPI instrumentation](https://opentelemetry-python-contrib.readthedocs.io/en/latest/instrumentation/fastapi/fastapi.html)
- [Opik LangChain integration guide](https://www.comet.com/tracing/integrations/langchain)
- [Opik OpenTelemetry overview](/guides/multi-language-opentelemetry)

## Related pages

- [Observability for AG2 with Opik](./python-ag2.md)
- [Observability for Agent Spec with Opik](./python-agentspec.md)
- [Observability for Agno with Opik](./python-agno.md)
- [Observability for BeeAI (Python) with Opik](./python-beeai.md)
- [Observability for Claude Agent SDK with Opik](./python-claude-agent-sdk.md)
- [Observability for AutoGen with Opik](./python-autogen.md)
- [Observability for CrewAI with Opik](./python-crewai.md)
- [Observability for DSPy with Opik](./python-dspy.md)
- [Observability for Google Agent Development Kit (Python) with Opik](./python-adk.md)
- [Observability for Haystack with Opik](./python-haystack.md)

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