LangChain

LangChain is a comprehensive ecosystem for building and deploying AI agents, consisting of open-source frameworks and an agent engineering platform called LangSmith. The company offers two main frameworks: LangChain, which enables rapid development with pre-built agent architectures and model integrations, and LangGraph, which provides low-level primitives for building custom agent workflows with greater control. LangSmith, their agent engineering platform, provides end-to-end capabilities for observability (tracing each step of agent execution for debugging), evaluation (building test sets from production data and scoring performance), and deployment (infrastructure designed for long-running agent workloads with memory, auto-scaling, and enterprise security). The platform is framework-neutral and works with any open-source framework or custom code, serving use cases like copilots, enterprise GPT, customer support automation, research synthesis, code generation, and AI search. With over 90 million monthly downloads, 100,000+ GitHub stars, and 1,000 integrations, LangChain powers top engineering teams from AI startups to global enterprises like Klarna, Elastic, and Rakuten, helping them ship reliable agents faster while maintaining visibility, control, and durable performance at scale.