LlamaIndex / llamaindex.ai
Open source Python framework for connecting AI models to private data sources, specialising in RAG, data ingestion, and multi-agent applications.
Free plan
Yes
API access
Yes
Open source
Yes
Platforms
2
LlamaIndex is an open source Python framework focused specifically on connecting AI models to private data sources and building retrieval-augmented generation (RAG) applications. While LangChain is a broader LLM application framework, LlamaIndex has a tighter focus on data ingestion, indexing, and retrieval that makes it the preferred choice for teams building document Q&A systems and knowledge bases.
The data connectors in LlamaIndex support ingesting documents from a wide range of sources: PDFs, Word documents, databases, APIs, web pages, Slack, Notion, and many others. These connectors handle the complexity of extracting text from diverse formats and preparing it for AI processing, which reduces the amount of custom data handling code developers need to write.
The indexing capabilities support various approaches to structuring data for retrieval, from simple vector search to more sophisticated hybrid approaches that combine semantic similarity with keyword matching. The choice of indexing strategy significantly affects retrieval quality, and LlamaIndex provides tools for experimenting with different approaches.
Querying across indexed data is LlamaIndex's most polished feature. Complex queries that require reasoning across multiple retrieved chunks, combining information from multiple sources, or applying filters to retrieved results are well-supported.
LlamaIndex has expanded into multi-agent applications, providing tools for building systems where multiple AI agents collaborate to complete tasks, building on its strength in data retrieval.
LlamaIndex runs as llm application framework software built around text and document workflows. Users typically start with a prompt, upload, or connected data source, and the underlying model handles the heavy lifting before returning a result you can refine or export. It's available on python and typescript, with API access for teams that want to embed it into their own products.
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The capabilities that matter most for teams evaluating LlamaIndex.
100+ connectors for ingesting documents from PDFs, databases, APIs, web pages, and SaaS tools into AI-ready format.
Tools for building retrieval-augmented generation systems with flexible indexing and query strategies.
Framework for building multi-agent applications where AI agents collaborate to answer complex queries across multiple data sources.
LlamaIndex framework is open source and free. LlamaCloud (managed service) has usage-based pricing. Enterprise support available.
Model
Open Source
Starting price
Free
Free trial
No
LangChain is a broader LLM application framework with a larger community. Haystack is another framework focused on document search and RAG. Direct API integrations are simpler for straightforward use cases.
A side-by-side look at the closest alternative in this category.
LlamaIndex
LlamaIndex
LangChain
LangChain
Key facts about model providers, platforms, and team support.
Model Provider
Agnostic (OpenAI, Anthropic, etc.)
Platforms
Python, TypeScript
Deployment
Open Source, SaaS (LlamaCloud)
Integrations
All major LLM providers, Vector databases (Pinecone, Weaviate, Chroma), AWS, Azure, GCP
Team Collaboration
No
Launch Year
2022
Compliance signals and data-handling notes as reported by the vendor.
Open source LlamaIndex: data stays within your infrastructure. LlamaCloud: review LlamaIndex's data handling policy. Enterprise includes data processing agreements.
Self-hosted LlamaIndex provides full data control. LlamaCloud processes data on LlamaIndex's infrastructure. Review privacy policy for cloud deployments with sensitive data.
Editorial Verdict
LlamaIndex is the best choice for teams specifically focused on RAG and data-connected AI applications. For broader LLM application development beyond data retrieval, LangChain provides more flexibility.
Last verified July 24, 2026.
LlamaCloud, the managed service built on LlamaIndex, provides hosted versions of data ingestion and retrieval infrastructure for teams that want to use LlamaIndex capabilities without managing the infrastructure themselves.
LlamaIndex framework is open source and free. LlamaCloud (managed service) has usage-based pricing. Enterprise support available.
LangChain framework is open source and free. LangSmith (observability platform) free up to 5,000 traces/month, Developer $39/month, Plus $99/month. Enterprise custom pricing.
Agnostic (OpenAI, Anthropic, Google, etc.)
Open source LlamaIndex: data stays within your infrastructure. LlamaCloud: review LlamaIndex's data handling policy. Enterprise includes data processing agreements.
LangSmith (cloud): review LangChain's privacy policy. Self-hosted LangChain: full data control within your infrastructure.
Self-hosted LlamaIndex provides full data control. LlamaCloud processes data on LlamaIndex's infrastructure. Review privacy policy for cloud deployments with sensitive data.
Open source LangChain: data stays within your infrastructure. LangSmith cloud: review LangChain's data handling policy. Enterprise LangSmith includes data processing agreements.
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