Quick reference for the four core LangChain ecosystem REST APIs.
| API | Base URL (US) | Base URL (EU) | OpenAPI Spec | Interactive Docs | Purpose |
|---|---|---|---|---|---|
| LangSmith API | https://api.smith.langchain.com |
https://eu.api.smith.langchain.com |
https://api.smith.langchain.com/openapi.json |
https://api.smith.langchain.com/redoc |
Tracing, evaluation, datasets, org management |
| LangSmith Deployment Control Plane API | https://api.host.langchain.com |
https://eu.api.host.langchain.com |
https://api.host.langchain.com/openapi.json |
https://api.host.langchain.com/docs |
Deployment management for LangGraph Server |
| LangSmith Deployment Agent Server API | Per-deployment | Per-deployment | /docs on each deployment |
/docs on each deployment |
Runtime API for assistants, threads, runs |
| SCIM API | https://api.smith.langchain.com/scim/v2 |
https://eu.api.smith.langchain.com/scim/v2 |
SCIM 2.0 compliant | N/A | User provisioning (Enterprise) |
For detailed information including authentication, endpoints, schemas, and usage examples, see LANGSMITH_APIS_DETAILS.md.