> ## Documentation Index
> Fetch the complete documentation index at: https://langchain-5e9cc07a-preview-opensw-1783460346-e74075c.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# LangSmith API reference

The LangSmith REST API provides programmatic access to LangSmith platform features including tracing, datasets, experiments, annotations, and more.

Browse the full API reference in the **LangSmith API** section in the sidebar.

## Authentication

Pass the `X-Api-Key` header with each request. The value should be a valid [LangSmith API key](/langsmith/create-account-api-key).

```shell theme={null}
curl --request GET \
  --url https://api.smith.langchain.com/api/v1/workspaces \
  --header 'X-Api-Key: LANGSMITH_API_KEY'
```

***

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