LangChain
San Francisco, United States
What it is
LangChain is a free, MIT-licensed open-source framework for building agents with models and tools. Its create_agent harness combines a model, tools, prompt, and middleware into a configurable agent, with templates for common use cases and a ReAct pattern. Middleware can add human approval, conversation compression, sensitive-data removal, guardrails, retries, routing, and custom tool policies. Agents run on LangGraph’s durable runtime, which provides persistence, rewind, checkpointing, and human-in-the-loop support. Documentation covers more than 1,000 integrations across chat and embedding models, tools, document loaders, and vector stores. Standard interfaces for chat models and embeddings support switching providers with minimal code changes. Installation examples cover Python and JavaScript/TypeScript. LangSmith can trace requests, aid debugging, and evaluate outputs. LangChain was started as a company in early 2023 and is headquartered in San Francisco. The framework is free; LangSmith plans add usage-based and enterprise options.
For and against
For
- Open-source MIT-licensed framework
- More than 1,000 documented integrations
- Configurable agent harness
- Durable runtime with checkpoints
- Python and JavaScript support
Against
- LangSmith usage can incur pay-as-you-go charges
- Developer plan has one seat
- Developer plan includes 5k base traces monthly
The verdict
LangChain supplies agent structure, integrations, middleware, and durable execution for self-hosted or API projects. The framework is free, while LangSmith adds tracing and evaluation with plan-specific limits and charges.
Who it suits
LangChain suits developers building model-and-tool agents in Python or JavaScript/TypeScript. It is useful when projects need integrations, configurable middleware, durable execution, or observability.
Plans and prices
Developer (LangSmith)
1 seat · Up to 5k base traces / mo, then pay-as-you-go · Community support
Read 4 Oct 2026 · langchain.com
LangChain framework
Open-source framework
Read 4 Oct 2026 · langchain.com
Plus (LangSmith)
Up to 10k base traces / mo, then pay-as-you-go · Add unlimited seats · 1 free Serverless (Small) deployment included
Read 4 Oct 2026 · langchain.com
Enterprise (LangSmith)
Self-hosted and hybrid deployment options · Custom SSO, ABAC, and RBAC · Support SLA · Custom seats and workspaces
Read 4 Oct 2026 · langchain.com
On the record
- Agent harness
- The `create_agent` harness composes a model, tools, prompt, and middleware into a configurable agent.docs.langchain.com · read 4 Oct 2026
- Agent patterns
- The framework provides templates for common use cases and a ReAct pattern through `create_agent`.langchain.com · read 4 Oct 2026
- Company
- LangChain says it was started as a company in early 2023 and is headquartered in San Francisco.langchain.com · read 4 Oct 2026
- Data use
- The LangSmith pricing FAQ states that customer data is not used to train models and remains private to the customer’s organization.langchain.com · read 4 Oct 2026
- Integrations
- LangChain documents 1000+ integrations across chat and embedding models, tools and toolkits, document loaders, and vector stores.docs.langchain.com · read 4 Oct 2026
- Languages
- The maker provides LangChain framework documentation and installation examples for Python and JavaScript/TypeScript.docs.langchain.com · read 4 Oct 2026
- Middleware
- Middleware can add human approval, conversation compression, sensitive-data removal, guardrails, retries, routing, and custom tool policies.langchain.com · read 4 Oct 2026
- Model portability
- LangChain provides a standard interface for chat models and embeddings across providers, allowing models to be switched with minimal code changes.docs.langchain.com · read 4 Oct 2026
- Notable limits
- The Developer plan includes one seat and up to 5k base traces per month before pay-as-you-go charges apply.langchain.com · read 4 Oct 2026
- Observability
- LangSmith can trace requests and help developers debug agent behavior and evaluate outputs from LangChain applications.docs.langchain.com · read 4 Oct 2026
- Purpose
- LangChain is an open-source framework that provides a pre-built agent architecture and integrations for models and tools.langchain.com · read 4 Oct 2026
- Runtime
- LangChain agents run on LangGraph’s durable runtime, with persistence, rewind, checkpointing, and human-in-the-loop support.langchain.com · read 4 Oct 2026
- Security compliance
- LangChain’s Trust Center lists SOC 2 Type II, ISO 27001:2022, GDPR, and HIPAA compliance for LangSmith.trust.langchain.com · read 4 Oct 2026
- Support
- The LangSmith Developer plan includes community support, while the Enterprise plan includes a support SLA.langchain.com · read 4 Oct 2026
