# LangChain ## Docs - [Building Custom Tools](https://mintlify.wiki/langchain-ai/langchain/advanced/custom-tools.md): Create custom tools to extend agent capabilities with your own functions and APIs - [Middleware System](https://mintlify.wiki/langchain-ai/langchain/advanced/middleware.md): Intercept and control agent execution with powerful middleware hooks - [Performance Optimization](https://mintlify.wiki/langchain-ai/langchain/advanced/performance.md): Optimize agent performance with caching, batching, and concurrent execution strategies - [Rate Limiting](https://mintlify.wiki/langchain-ai/langchain/advanced/rate-limiting.md): Control API usage and prevent quota exhaustion with built-in rate limiting - [Document Loaders](https://mintlify.wiki/langchain-ai/langchain/api/core/document-loaders.md): Base classes for loading documents from various sources - [Language Models](https://mintlify.wiki/langchain-ai/langchain/api/core/language-models.md): Base classes for chat models and LLMs - [Messages](https://mintlify.wiki/langchain-ai/langchain/api/core/messages.md): Message types for chat-based interactions - [Output Parsers](https://mintlify.wiki/langchain-ai/langchain/api/core/output-parsers.md): Classes for parsing and structuring LLM outputs - [Prompt Templates](https://mintlify.wiki/langchain-ai/langchain/api/core/prompts.md): Template classes for creating dynamic prompts - [Retrievers](https://mintlify.wiki/langchain-ai/langchain/api/core/retrievers.md): Base classes for document retrieval - [Runnables](https://mintlify.wiki/langchain-ai/langchain/api/core/runnables.md): Base classes for building composable LangChain components - [Vector Stores](https://mintlify.wiki/langchain-ai/langchain/api/core/vectorstores.md): Interfaces for vector storage and similarity search - [Agents](https://mintlify.wiki/langchain-ai/langchain/api/langchain/agents.md): Agent creation and state management - [Chat Models](https://mintlify.wiki/langchain-ai/langchain/api/langchain/chat-models.md): Chat model initialization and configuration - [Embeddings](https://mintlify.wiki/langchain-ai/langchain/api/langchain/embeddings.md): Embedding model initialization and configuration - [Rate Limiters](https://mintlify.wiki/langchain-ai/langchain/api/langchain/rate-limiters.md): Rate limiting for API requests - [Tools](https://mintlify.wiki/langchain-ai/langchain/api/langchain/tools.md): Tool definitions and runtime utilities - [Agent Concepts](https://mintlify.wiki/langchain-ai/langchain/concepts/agents.md): Building autonomous agents that use tools and reason through multi-step tasks - [Framework Architecture](https://mintlify.wiki/langchain-ai/langchain/concepts/architecture.md): Understanding LangChain's modular monorepo structure and layered design - [Chains](https://mintlify.wiki/langchain-ai/langchain/concepts/chains.md): Composing components into deterministic sequences with LangChain Expression Language - [Messages](https://mintlify.wiki/langchain-ai/langchain/concepts/messages.md): Understanding message types and structure for chat-based interactions in LangChain - [Runnables and LCEL](https://mintlify.wiki/langchain-ai/langchain/concepts/runnables.md): Understanding the Runnable protocol and LangChain Expression Language for composable AI applications - [Tools](https://mintlify.wiki/langchain-ai/langchain/concepts/tools.md): Building and integrating tools for agent actions and model interactions - [Building Agents](https://mintlify.wiki/langchain-ai/langchain/guides/building-agents.md): Learn how to build agents that can use tools and make decisions - [Working with Chat Models](https://mintlify.wiki/langchain-ai/langchain/guides/chat-models.md): Learn how to use chat models for conversational AI applications - [Debugging Applications](https://mintlify.wiki/langchain-ai/langchain/guides/debugging.md): Debug and troubleshoot LangChain applications effectively - [Using Embeddings](https://mintlify.wiki/langchain-ai/langchain/guides/embeddings.md): Convert text to vectors for semantic search and similarity - [Output Parsing](https://mintlify.wiki/langchain-ai/langchain/guides/output-parsing.md): Extract structured data from LLM outputs - [Retrieval (RAG)](https://mintlify.wiki/langchain-ai/langchain/guides/retrieval.md): Build retrieval-augmented generation systems with LangChain - [Streaming Responses](https://mintlify.wiki/langchain-ai/langchain/guides/streaming.md): Stream LLM outputs for real-time user experiences - [Installation](https://mintlify.wiki/langchain-ai/langchain/installation.md): Install LangChain and configure your development environment - [Anthropic](https://mintlify.wiki/langchain-ai/langchain/integrations/chat-models/anthropic.md) - [DeepSeek](https://mintlify.wiki/langchain-ai/langchain/integrations/chat-models/deepseek.md) - [Fireworks](https://mintlify.wiki/langchain-ai/langchain/integrations/chat-models/fireworks.md) - [Groq](https://mintlify.wiki/langchain-ai/langchain/integrations/chat-models/groq.md) - [Mistral AI](https://mintlify.wiki/langchain-ai/langchain/integrations/chat-models/mistralai.md) - [Ollama](https://mintlify.wiki/langchain-ai/langchain/integrations/chat-models/ollama.md) - [OpenAI](https://mintlify.wiki/langchain-ai/langchain/integrations/chat-models/openai.md) - [Perplexity](https://mintlify.wiki/langchain-ai/langchain/integrations/chat-models/perplexity.md) - [xAI](https://mintlify.wiki/langchain-ai/langchain/integrations/chat-models/xai.md) - [HuggingFace Embeddings](https://mintlify.wiki/langchain-ai/langchain/integrations/embeddings/huggingface.md): Embed text using HuggingFace sentence-transformers models - [Nomic Embeddings](https://mintlify.wiki/langchain-ai/langchain/integrations/embeddings/nomic.md): Embed text and images using Nomic's embedding models - [Ollama Embeddings](https://mintlify.wiki/langchain-ai/langchain/integrations/embeddings/ollama.md): Embed text using locally-hosted Ollama models - [OpenAI Embeddings](https://mintlify.wiki/langchain-ai/langchain/integrations/embeddings/openai.md): Embed text using OpenAI's embedding models - [Integrations Overview](https://mintlify.wiki/langchain-ai/langchain/integrations/overview.md): Explore LangChain's ecosystem of integrations for chat models, embeddings, vector stores, and tools - [Exa](https://mintlify.wiki/langchain-ai/langchain/integrations/tools/exa.md): Search and retrieve web content using Exa's neural search API - [OpenRouter](https://mintlify.wiki/langchain-ai/langchain/integrations/tools/openrouter.md): Access hundreds of AI models through a unified API with OpenRouter - [Chroma](https://mintlify.wiki/langchain-ai/langchain/integrations/vectorstores/chroma.md) - [Qdrant](https://mintlify.wiki/langchain-ai/langchain/integrations/vectorstores/qdrant.md) - [Introduction](https://mintlify.wiki/langchain-ai/langchain/introduction.md): Build agents and LLM-powered applications with composable components - [Quickstart](https://mintlify.wiki/langchain-ai/langchain/quickstart.md): Build your first LLM application with LangChain in minutes ## OpenAPI Specs - [openapi](https://mintlify.wiki/langchain-ai/langchain/api-reference/openapi.json)