Observability for LangServe with Opik
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
Section titled “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
Section titled “Opik OTLP endpoint modes”For full endpoint/header details, see Opik OpenTelemetry overview.
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
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
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
Section titled “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:
Validation
Section titled “Validation”- Send a request through a LangServe endpoint.
- Confirm a root HTTP/server span is emitted from your host app.
- Confirm downstream LangChain/LangServe-related spans are exported and visible in Opik.