LangChain

LangChain started as Harrison Chase's side project in late 2022 as a single Python package before becoming a company in early 2023. The company’s own About page identifies this as the origin of LangChain.

LangChain disclosed a $10 million seed round led by Benchmark. Reporting at the time also noted that Sequoia was in discussions to lead a later round at a valuation of at least $200 million.

LangChain announced a $25 million Series A led by Sequoia Capital. The company said the raise came alongside the general availability launch of LangSmith.

LangChain announced general availability of LangSmith, its commercial platform for observability, evaluation, and deployment of LLM applications. The company positioned it as a key part of its product suite alongside open-source frameworks.

LangChain’s own 2024 State of AI report states that LangGraph was released in March 2024. The report describes LangGraph as the company’s controllable agent framework for more complex agentic workflows.

$125M Series B announced Oct 2025.

LangChain announced a $125 million Series B at a $1.25 billion valuation. The round was led by IVP with participation from existing and new investors, and the company also announced LangChain 1.0 and LangGraph 1.0 releases.