LangChain

Verified

The most popular framework for building LLM applications — chains, agents, and RAG made easy.

4.4

Open sourceAI Agents

Pricing

Open source

About LangChain

LangChain is the dominant open-source framework for building applications with large language models. It provides composable components for chains, agents, RAG, memory, and tool use. Available in Python and JavaScript with LangSmith for observability.

Key Features

Composable LLM application framework
Agent and tool use support
RAG and retrieval pipelines
LangSmith for debugging and monitoring
Python and JavaScript SDKs

Pros & Cons

Pros

+ Largest LLM framework ecosystem

+ Excellent documentation

+ Huge integration library

Cons

- Can be over-abstracted for simple tasks

- Frequent breaking changes

- Learning curve for the full framework

Use Cases

Building RAG applicationsCreating AI agentsLLM application developmentPrototyping AI workflows

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Self-hostable, forkable, no vendor lock-in.