langchain-ai/langserve

Health v2 · maintenance only

Flags: archived no_license

Adoption not part of the score

2330 stars · 272 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

LangServe is a Python library that deploys LangChain runnables and chains as REST APIs built on FastAPI, with automatic input/output schema validation, invoke/batch/stream endpoints, and a built-in playground UI. It also ships a client SDK (with a JavaScript client in LangChain.js) for calling remote runnables as if they were local, though the project is deprecated in favor of LangGraph Platform.

Use cases

• deploy a langchain chain as a rest api
• serve an llm app with fastapi endpoints
• expose a langchain runnable over http
• stream llm responses and intermediate steps to a frontend
• test langchain chains in an interactive playground
• call a deployed langchain server from javascript

When to choose

• you are maintaining an existing LangServe-based deployment and need community bug fixes
• you need to quickly expose simple LangChain runnables as invoke/batch/stream REST endpoints with automatic schemas
• you want a built-in playground and optional LangSmith tracing for a FastAPI-served chain

When to avoid

• starting a new project, since LangServe is deprecated in favor of LangGraph Platform
• deploying LangGraph graphs or agents, which it is not designed for
• you need new features or long-term official support, as only community bug fixes are accepted

Facets

library · maturity maintenance

deployment api-framework http-server sdk llm-inference large-language-models artificial-intelligence apis backend web-development developer-tools python langchain fastapi pydantic rest-api streaming playground langsmith-tracing runnables deprecated web-server

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markdown · JSON · MCP: product_card(name="langchain-ai/langserve")