LangChain vs LlamaIndex

LangChain

The default starting point for agent development: no other framework matches its integration catalog, documentation volume or hiring-market familiarity. The catch is churn and depth — major versions have repeatedly rewritten core APIs, and once you need observability or managed deployment you are steered toward the paid LangSmith platform.

Pros

• +Integrations for 1,000+ models, tools, vector stores and databases
• +MIT license with a large contributor community
• +LangGraph runtime adds persistence, rewind and human-in-the-loop control
• +Python and JavaScript keep parity for most features

Cons

• −History of breaking API changes between major versions
• −Layers of abstraction complicate debugging versus direct SDK calls
• −Production observability and deployment funnel into commercial LangSmith

LlamaIndex

LlamaIndex is the pragmatic choice for a developer who wants retrieval over messy documents working this week: the open-source framework handles ingestion and querying, and LlamaParse does the hard part — tables, scans and layouts — as a paid API with a free tier large enough to prototype on. Teams that only need to chain model calls will find LangChain's ecosystem broader, and anyone parsing millions of pages should model the credit cost before committing, because agentic parsing multiplies the per-page rate.

Pros

• +Open-source framework with commercial-friendly licensing and connectors for most file and data sources
• +LlamaParse handles tables, multi-column layouts and scanned pages that plain text extractors mangle
• +Free tier of 10,000 credits a month and a $50 Starter plan make the cost curve gentle at the start
• +Enterprise options include private VPC and hybrid deployment, SSO and custom BAAs

Cons

• −Credit pricing is opaque until you test: basic pages cost one credit, agentic and VLM parsing cost several times more
• −The free tier allows file upload only, so connectors and external sources need a paid plan
• −Rapid API and library changes mean tutorials and integrations go stale quickly
• −Index limits (5 indexes, 50 files each on Free) are tight for anything beyond a demo

Is LangChain cheaper than LlamaIndex?

LangChain is free to use; LlamaIndex starts at $50/mo.

Does LangChain or LlamaIndex have a free tier?

Both: LangChain is free to use, and LlamaIndex has a free tier.

Which has a public API, LangChain or LlamaIndex?

LlamaIndex ships a public API, as of our last verification. A public API for LangChain is not confirmed by us — check its developer docs before you plan an integration.