LangChain
LangChain provides open-source frameworks for building AI agents and LangSmith, a platform to trace, evaluate, deploy and monitor them in production.
About this tool
LangChain is best known for its open-source libraries that help developers connect language models to tools, data and memory to build agents. The company frames its work around an agent development lifecycle: start from proven patterns, keep control over your model choice, context and memory, and customise them when a project demands it.
LangSmith, its commercial platform, covers what comes after the first prototype. It records step-by-step traces of agent runs for debugging, turns traces into datasets and evaluations, deploys agents on infrastructure designed for long-running tasks and persistent state, runs agent-generated code in sandboxes, and monitors cost, latency and errors in production. A no-code option lets other teams build agents in natural language.
What you can do
Open-source agent frameworks
Libraries for connecting models to tools, retrieval and memory, with patterns for building agents in code.
Tracing and debugging
LangSmith records each step of an agent run so developers can see where reasoning or tool calls went wrong.
Evaluations
Turn real traces and expert reviews into datasets and evaluations to test behaviour before shipping changes.
Deployment and monitoring
Managed deployment for long-running agents, sandboxed code execution, and production dashboards and alerts.
Who is it for?
- An engineering team debugs why a support agent picked the wrong tool.
- A product team runs evaluations on every prompt change before release.
- A company deploys long-running research agents with persistent state.
Before you choose
Usage-based pricing for traces and deployment units can grow with traffic; LangChain notes its cost estimates vary with agent workload.
Frameworks evolve quickly, so pin versions and plan time for upgrades when building production systems.
Frequently asked questions
Is LangChain free?
The open-source frameworks are free. LangSmith has a free Developer plan with one seat and 5,000 base traces a month.
What is LangSmith?
LangSmith is LangChain’s platform for tracing, evaluating, deploying and monitoring AI agents, usable with or without LangChain’s frameworks.
Can LangSmith be self-hosted?
LangChain lists self-hosted and hybrid deployment options on its Enterprise plan.
Check the official website for current features, pricing, and terms.
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