LangChain vs LlamaIndex
LangChain is an open source framework for building LLM applications through chains, agents, tools and memory, paired with LangSmith, a paid observability and deployment platform. LlamaIndex is an open source framework focused on connecting language models to external data, documents, databases and APIs, for retrieval-augmented generation, paired with LlamaParse, a paid document parsing platform. Choose LangChain for building general-purpose agents and workflows; choose LlamaIndex if your application centers on retrieving and parsing your own data.
Facts checked on against the official sources listed at the end. Usage numbers update daily.
Best for
General-purpose LLM applications built around chains, agents and tool use
Free plan. Paid from $39 a seat a month for LangSmith Plus, plus usage-based compute and storage.
Best for
Retrieval-augmented generation apps centered on parsing and indexing your own data
Free plan. Paid from $50 a month for the LlamaParse Starter plan.
LangChain vs LlamaIndex at a glance
| Compared on | LangChain | LlamaIndex |
|---|---|---|
| Core focus | Chains, agents, tools and memory for general LLM applications | Data connectors, indexing and retrieval for RAG and agent apps |
| Companion commercial product | LangSmith: observability, evaluation and deployment | LlamaParse: commercial document parsing |
| Companion product free tier | Up to 5,000 base traces a month, 1 seat | 10,000 credits |
| Companion product entry paid price | $39 a seat a month (LangSmith Plus) | $50 a month (LlamaParse Starter) |
| Companion product billing unit | Per seat, plus usage-based compute and storage | Credit system: 1,000 credits cost $1.25 |
| Primary language support | Python and JavaScript/TypeScript | Python and TypeScript |
| Open source | Yes, MIT | Yes, MIT |
| Free plan | Yes: the LangChain framework is free and open source; LangSmith has a free Developer tier with up to 5,000 base traces a month | Yes: the LlamaIndex framework is free and open source; LlamaParse has a free tier with 10,000 credits |
| Paid plans from | $39 a seat a month for LangSmith Plus, plus usage-based compute and storage | $50 a month for the LlamaParse Starter plan |
| Made by | LangChain, Inc. | LlamaIndex, Inc. |
What's the difference between LangChain and LlamaIndex?
LangChain centers on chains and agents, LlamaIndex centers on data connection
LangChain's core abstractions are chains, agents, tools and memory, aimed at building general-purpose LLM applications and workflows. LlamaIndex's core focus is connecting language models to external data sources, documents, databases and APIs, specifically for retrieval-augmented generation.
Their paid companion products solve different problems
LangChain's LangSmith is an observability, evaluation and deployment platform for monitoring how your LLM application behaves in production. LlamaIndex's LlamaParse is a document parsing platform, converting complex documents like PDFs into clean text or structured data for retrieval, a narrower and more specific commercial product.
The companion products bill on different units entirely
LangSmith prices per seat, at $39 a seat a month on Plus, plus usage-based compute and storage. LlamaParse prices on a credit system, where 1,000 credits cost $1.25, with plans bundling a set number of included credits rather than seats.
LangChain's Workflows overlap conceptually with LlamaIndex's Workflows
Both frameworks have converged on a similar workflow concept for orchestrating multi-step LLM logic, LangChain's chains and agents versus LlamaIndex's own Workflows feature, so teams evaluating either framework for orchestration alone will find comparable, if not identical, capabilities.
LangChain vs LlamaIndex pricing
Both core frameworks are free and open source under MIT. Their paid companion products, LangSmith and LlamaParse, bill on different units, seats versus credits.
LangChain
The framework is free and open source. LangSmith Developer is free (5,000 traces a month, 1 seat). LangSmith Plus is $39 a seat a month (10,000 traces a month, unlimited seats), plus usage-based compute and storage. Enterprise is custom.
- LangChain framework
- $0, open source
- LangSmith Developer
- $0 a seat a month
- LangSmith Plus
- $39 a seat a month
- LangSmith Enterprise
- Custom pricing
LlamaIndex
The framework and Workflows are free and open source. LlamaParse Free includes 10,000 credits. LlamaParse Starter is $50 a month (40,000 credits included). LlamaParse Pro is $500 a month (400,000 credits included). Enterprise is custom.
- LlamaIndex framework
- $0, open source
- LlamaParse Free
- $0 a month
- LlamaParse Starter
- $50 a month
- LlamaParse Pro
- $500 a month
- LlamaParse Enterprise
- Custom pricing
Prices in USD from the official pricing pages on 30 September 2026. They change often, so confirm on langchain.com and llamaindex.ai before you commit.
Usage and activity
LangChain has 2.8 times as many GitHub stars as LlamaIndex (148k against 52.5k). Weekly npm downloads: 3.7M for langchain and 159k for llamaindex. Releases on GitHub in the last 90 days: 10 for LangChain and 2 for LlamaIndex.
| Measure | LangChain | LlamaIndex |
|---|---|---|
| GitHub stars | 147,950 | 52,528 |
| npm downloads a week | 3.7M (langchain) | 159k (llamaindex) |
| Latest release | langchain-core==…, 8 hours ago | v0.14.25, 3 weeks ago |
| Releases in 90 days | 10 | 2 |
From the public GitHub and npm APIs, updated daily. Stars and downloads show developer interest, not product quality.
Should you choose LangChain or LlamaIndex?
Choose LangChain if
- You're building general-purpose agents, chatbots or multi-step LLM workflows
- You want production observability and evaluation tooling through LangSmith
- You want a per-seat pricing model for your team's usage of the observability platform
- You need broad integrations across many different LLM providers and tools
Choose LlamaIndex if
- Your application is centered on retrieval-augmented generation over your own documents
- You need to parse complex documents like PDFs into clean, structured text for retrieval
- You'd rather pay by usage credits than per seat for your companion platform
- You want data connectors purpose-built for indexing databases and APIs alongside documents
Switching between LangChain and LlamaIndex
Both frameworks can coexist in the same application, since LlamaIndex is often used for its data connectors and retrieval pipeline while LangChain orchestrates the broader agent logic around it. A full switch from one to the other means rewriting chains or agents in the other framework's abstractions, and migrating any LangSmith traces or LlamaParse parsing configurations to the other's companion product if you use those.
LangChain vs LlamaIndex: common questions
Are LangChain and LlamaIndex free?
Yes, both core frameworks are free and open source under the MIT license. Their paid companion products, LangSmith and LlamaParse, have separate pricing.
Can I use LangChain and LlamaIndex together?
Yes, it's common to use LlamaIndex's data connectors and retrieval pipeline inside a LangChain-orchestrated application, since the two frameworks address different parts of an LLM application.
What is LangSmith?
LangChain's paid platform for observability, evaluation and deployment of LLM applications, with a free Developer tier and paid Plus and Enterprise tiers.
What is LlamaParse?
LlamaIndex's paid document parsing platform, converting complex documents like PDFs into clean text or structured data for retrieval, priced on a credit system.
Which is better for retrieval-augmented generation?
LlamaIndex is built specifically around connecting data for retrieval-augmented generation, though LangChain also supports RAG patterns as part of its broader chain and agent framework.
Other options to consider
All llm frameworks tools
Vercel AI SDK
Free open source TypeScript toolkit from Vercel for building AI apps and agents across many model providers.
CrewAI
MIT-licensed Python framework for multi-agent workflows, with a paid platform for deployment.
Mastra
TypeScript framework for AI agents and workflows, Apache 2.0 licensed, with a managed platform.
LangGraph
Low-level orchestration framework from LangChain for long-running, stateful agents.
Sources
More sources for each tool are on the LangChain and LlamaIndex pages.