What is LangChain?

LangChain has become the de facto standard for building LLM-powered applications. It provides the abstractions that turn a raw language model into a functional agent — tool calling, memory management, retrieval pipelines, and multi-step reasoning chains.

For developers building AI agents that interact with external systems, LangChain's agent framework handles the orchestration: the LLM decides which tools to call, processes results, and iterates until the task is complete. This is particularly relevant for financial agents that need to check balances, execute swaps, or process payments.

The framework's modular design means you can swap out models, vector stores, and tools without rewriting your application — making it a practical foundation for production agent systems.

LangChain agents that call financial tools — wallet transfers, DeFi swaps, payment APIs — need policy enforcement at the tool boundary. PolicyLayer integrates as a tool wrapper, validating every financial action against spending policies before execution reaches the blockchain.