Skip to content
Langchain logo

Langchain

Verified

LangChain enables creation of customizable AI agents through modular components and model integrations.

Open SourceCoding & Dev
Visit website
Free to browse · updated 2026-06-14
Langchain screenshot

What is Langchain?

LangChain centers on building agents by pairing a language model with supporting elements like custom tools and system prompts. Developers can start with core primitives and extend functionality through middleware that addresses individual concerns such as context handling or output structuring. The framework emphasizes flexibility, allowing seamless swapping of models from different providers without altering surrounding code. Agents created this way gain access to durable execution features and human oversight options through their foundation in LangGraph. Integration with LangSmith adds capabilities for monitoring execution paths, capturing state changes, and generating runtime metrics to refine agent performance over time.

Key features

create_agent function for building customizable agents with models and tools
Standard interface supporting OpenAI, Anthropic, Google Gemini, and other providers
Highly configurable harness with middleware for prompts, tools, and behavior
Built on LangGraph for durable execution and human-in-the-loop support
LangSmith integration for tracing, debugging, and evaluation
Support for custom tools, system prompts, and structured outputs
Streaming, memory, and multi-agent capabilities

What you can use Langchain for

Building Custom Tool-Enabled Agents

Develop agents that incorporate user-defined functions such as weather lookups or data queries, combined with a system prompt to guide behavior and produce structured responses via the create_agent function.

Switching Between Multiple LLM Providers

Leverage the standard interface to connect the same agent harness to models from OpenAI, Anthropic, Google Gemini, or other supported providers without changing core code.

Tracing and Evaluating Agent Workflows

Integrate LangSmith to capture execution traces, debug complex multi-step interactions, and evaluate outputs while using LangGraph for durable execution and human-in-the-loop oversight.

How to use Langchain

  1. 1Install LangChain and the desired model provider package
  2. 2Define custom tools as Python functions with docstrings
  3. 3Call create_agent with model identifier, tools list, and system prompt
  4. 4Invoke the agent using a messages array containing user input
  5. 5Enable LangSmith tracing by setting environment variables for debugging

Langchain pricing

Pricing model: Open Source. Plan details are indicative — check the site for current prices.

Open Source

Free
  • Core framework access
  • Agent creation
  • Model integrations

Editor's verdict

Pros

  • +Seamless provider swapping without lock-in
  • +Minimal yet extensible agent harness
  • +Deep runtime visibility via LangSmith

Cons

  • Some documentation pages return 404 errors
  • Requires coding to implement agents

Our take: Langchain is a solid coding & dev choice. It's valued for seamless provider swapping without lock-in and minimal yet extensible agent harness. The main trade-off is some documentation pages return 404 errors. A good pick if you want capable AI without a high upfront cost.

Frequently asked questions

It supplies a minimal, configurable harness that combines a model, tools, prompt, and execution loop, extendable through middleware.

Summary

Langchain is a solid coding & dev choice. It's valued for seamless provider swapping without lock-in and minimal yet extensible agent harness. The main trade-off is some documentation pages return 404 errors. A good pick if you want capable AI without a high upfront cost.

Did you find this helpful?

User reviews

Verified reviews from the community shape this tool's rating.

Loading reviews…

Sign in to review

Langchain alternatives

Similar coding & dev tools worth comparing.

Promote Langchain

Add this badge to your website, or share the tool.

DFeatured on DhanasviLangchain 0