ai-framework
LangChain
The framework for building LLM apps — chains, agents, RAG, LangGraph
Dominant OSS framework for LLM apps. LangChain (chains), LangGraph (stateful agents), LangSmith (obs). Python + JS/TS. MIT-licensed core.
Pricing
| Tier | Price | Notes |
|---|---|---|
| OSS (MIT) | Free | MIT-licensed core library. Free forever. Python + JS. |
| LangSmith (see entry) | Free | Observability layer — Developer free, Plus $39/seat. Separate platform. |
| LangGraph Platform — Developer | Free | Deploy LangGraph agents as an API. Free tier — limited execution minutes. |
| LangGraph Platform — Plus | $39/mo | $39/seat/mo (tied to LangSmith Plus). More execution credit. Production features. |
| Enterprise | Custom | Custom. Self-host, dedicated support, SSO. |
Limits
| Tier | Metric | Value | Notes |
|---|---|---|---|
| — | community size | 4M+ monthly downloads. Largest LLM framework ecosystem. | Community scale |
| — | ecosystem | LangChain (chains) + LangGraph (stateful agents) + LangSmith (obs) + LangServe (deploy) + LangGraph Platform (managed) | Product stack |
| — | integrations count | 700+ LLMs, vector stores, tools, document loaders | Integration count |
| — | langgraph focus | Stateful multi-actor workflows with human-in-the-loop | LangGraph model |
| — | license | MIT (core) + various for optional packages | License |
| — | primary patterns | Chains, Agents, RAG, Tool Use, Structured Outputs | Core patterns |
| — | supported languages | Python (primary), JavaScript/TypeScript | SDK languages |
Features
- Agents — Tool-using agents with reasoning loops. · docs
- Chains (LCEL) — LangChain Expression Language — pipe primitives into chains. · docs
- Checkpointers (LangGraph) — Persist agent state to SQL, Mongo, Redis, Postgres.
- Document Loaders — 150+ loaders for PDF, HTML, Notion, Google Drive, S3, GitHub, etc.
- Human-in-the-loop — Pause agent for approval, then resume.
- LangGraph — Stateful graph-based agent runtime. Durable, replayable, human-in-the-loop. · docs
- LangGraph Platform — Managed hosting for LangGraph agents with state persistence.
- LangGraph Studio — Desktop IDE for debugging agent graphs.
- LangServe — Deploy chains as FastAPI endpoints.
- Memory — Buffer, summary, entity, vector memory stores.
- Output Parsers — Structured JSON, Pydantic schemas, function calling.
- Prompt Templates — Templating + partial filling + output parsers.
- RAG (Retrieval-Augmented Generation) — Standard patterns + 50+ retrievers. · docs
- Streaming — First-class streaming at every layer.
- Subgraphs — Compose agent graphs hierarchically.
- Text Splitters — Recursive, token, semantic splitters for chunking.
- Tools — 400+ pre-built tools (web search, code, databases, APIs).
- Vector Store Integrations — 60+ vector DBs (Pinecone, Chroma, Weaviate, PGVector, Qdrant, Milvus).
Developer interfaces
| Slug | Name | Kind | Version |
|---|---|---|---|
| sdk-node | @langchain/core (Node) | sdk | 0.3.x |
| sdk-python | langchain (Python) | sdk | 0.3.x |
| langgraph-js | langgraph (JS) | sdk | 0.2.x |
| langgraph-platform | LangGraph Platform | rest | v1 |
| langgraph-py | langgraph (Python) | sdk | 0.3.x |
| langserve | LangServe | sdk | 0.3.x |
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Staxly is an independent catalog of developer platforms. Outbound links to LangChain are plain references to their official pages. Pricing is verified at publication time — reconfirm on the vendor site before buying.