HowToBuildAI Tools · Framework
LangChain
An open-source framework for applications built around language models.
- License
- MIT
- Cost
- Open Source
- Self-host
- Yes
Overview
LangChain provides model integrations and composable application patterns across Python and JavaScript ecosystems.
Why it is interesting
Why pay attention
Its broad integration surface makes it useful for evaluating and assembling changing AI application components.
Editorial status
Included for comparison and context.
Best for
- AI applications that need many provider integrations
- Teams prototyping agent and retrieval workflows
Not ideal for
- Small model calls where a provider SDK is sufficient
Open source & pricing
Open Source
Core libraries are free and self-hostable; related hosted services have separate plans.
GitHub momentum
★ 146,477
- Last 7 days
- +441
- Last 30 days
- Window incomplete
- Evidence
- 9/10/2026–9/17/2026 · weekly window
Sources checked
Canonical project facts and open-source licensemaintainer · Sep 4, 2026
Hosted-service pricing classificationmaintainer · Sep 4, 2026