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LangChain.js

JavaScript and TypeScript framework of interoperable components for building LLM apps and agents, with LangGraph.js and Deep Agents above it.

Harness by LangChain

IndexedMIT★ 18,292
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npm install langchain

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About

LangChain.js is the JavaScript version of LangChain, installed from npm, offering a standard interface for agents, models, embeddings and vector stores. Higher-level agent behavior such as planning and sub-agents comes from Deep Agents, and controllable workflows from LangGraph.js. LangSmith provides debugging, evaluation and monitoring, and LangSmith Deployment hosts long-running stateful agents.

Use cases: agent-orchestration, knowledge-base

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Fact sheet

Languages
TypeScript, JavaScriptREADME
Packages
langchain (npm)README
Observability
LangSmithREADME
Deploys to
langsmith-deploymentREADME
Maturity
Betagithub.com

Facts extracted by Claude Sonnet 5.5 from the linked sources on Oct 24, 2026; reviewed Oct 24, 2026. Wrong fact? Tell us.

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    Featured in

    Signals

    Stars
    18,292
    Forks
    3,455
    Open issues
    271
    Last commit
    Oct 23, 2026 (7 days ago)
    Last release
    Oct 22, 2026 (8 days ago)

    From GitHub (fetched Oct 24, 2026).

    Details

    Packages
    npm langchain
    License
    MIT
    Repository
    github.com/langchain-ai/langchainjs
    Website
    docs.langchain.com/langchain/
    Docs
    docs.langchain.com/
    First seen
    Oct 24, 2026
    Last checked
    Oct 24, 2026
    Source
    DocsREADMEgithub-graphql

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    Cite this page

    LangChain.js. Agent Mart. https://agentmart.dev/harnesses/langchain-js (last updated 2026-10-24)