LlamaIndex vs LangChain

LlamaIndex

LangChain

LlamaIndex · 16 features

• Agents — Agent patterns: ReAct, function-calling, multi-agent workflows.
• Document Readers — 200+ readers for PDF, web, Google Drive, SharePoint, Notion, S3, Slack.
• Evaluations — Built-in eval framework: faithfulness, context precision/recall.
• LlamaCloud — Managed indexing + retrieval platform. File connectors, auto-chunking, retrieval…
• LlamaExtract — Schema-based structured extraction from unstructured docs.
• LlamaHub — Community marketplace of readers, tools, prompts.
• LlamaParse — Best-in-class PDF + complex document parser. Tables, math, layout preserved.
• Multimodal — Image + text models, image retrieval.
• Node Parsers — Document chunkers: token, sentence, semantic, hierarchical.
• Observability (OpenLLMetry) — OTel-based tracing baked in.
• Property Graph — Graph-based RAG (knowledge graphs from unstructured data).
• Query Engines — Retrieval + response synthesis combos — router, sub-question, tree, etc.
• RAG — End-to-end RAG patterns: ingest → index → retrieve → synthesize.
• Tools — 50+ pre-built tool integrations.
• Vector Store Integrations — 50+ vector DB integrations.
• Workflows — Event-driven agent workflows (AgentWorkflow).

LangChain · 18 features

• Agents — Tool-using agents with reasoning loops.
• Chains (LCEL) — LangChain Expression Language — pipe primitives into chains.
• 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.
• 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.
• 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).