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Langchain

Free

The agent engineering platform.

FreeFree tier
Type
Open Source

About Langchain

LangChain is an open-source framework for building LLM-powered agents with a minimal and highly configurable harness called create_agent. It allows developers to compose agents by integrating prompts, tools, and middleware, and supports multiple LLM providers including OpenAI, Anthropic, Google, and more. The ecosystem includes Deep Agents for a batteries-included experience with automatic context compression, a virtual filesystem, and subagent-spawning, as well as LangGraph for low-level orchestration and LangSmith for tracing, debugging, and evaluating agents. LangChain is available under the MIT license and has a large community.

Key Features

Minimal and highly configurable agent harness via create_agent
Support for multiple LLM providers (OpenAI, Anthropic, Google, etc.)
Deep Agents with automatic context compression, virtual filesystem, and subagent-spawning
LangGraph for combining deterministic and agentic workflows
LangSmith for tracing, debugging, and evaluating agents
Open-source under MIT license (Python)

Pros & Cons

Pros
  • Highly configurable and minimal agent harness
  • Broad model provider support (OpenAI, Anthropic, Google, etc.)
  • Includes Deep Agents for out-of-the-box advanced features
  • Integrated tracing, debugging, and evaluation with LangSmith
  • Open source with MIT license and large community

Best For

Building custom agent applications with tool integrationOrchestrating complex multi-step AI workflowsTracing and debugging LLM agent behaviorPrototyping and production deployment of AI agents