LangChain was founded in 2022 by Harrison Chase in San Francisco. What started as an open-source Python library for chaining LLM calls quickly became one of the most popular AI development frameworks, with millions of monthly downloads.
The company raised $35 million across multiple rounds, including a $25 million Series A led by Sequoia Capital in 2023 at a $200 million valuation. This rapid funding reflected LangChain’s position as essential infrastructure for the emerging LLM application stack.
LangChain’s framework provides abstractions for common LLM patterns: prompt management, output parsing, memory, retrieval-augmented generation, tool use, and autonomous agents. The library supports all major model providers and integrates with hundreds of third-party tools and data sources.
Beyond the open-source framework, the company offers LangSmith — a platform for debugging, testing, and monitoring LLM applications in production. LangGraph, their newer product, enables developers to build complex multi-step agent workflows with explicit control flow.
With over 80,000 GitHub stars and a large contributor base, LangChain has become the default starting point for many developers building LLM-powered applications. The company employs around 60 people and hosts an active developer community through meetups and an online forum.
