Haystack

Open-source Python framework from deepset for building production RAG pipelines and LLM agents.

Freemium· Open-source free; deepset Enterprise Support and AI Platform via salesRAGMulti-model

Best for

Pick Haystack if you want a code-first, open-source Python framework to ship RAG or agent pipelines you can actually inspect and run in production.

Skip if

Skip it if you want a no-code agent builder or a hosted RAG-as-a-service and don't want to manage a Python stack.

Haystack is deepset's open-source framework for assembling LLM applications out of composable, serializable pipelines. You wire together components (retrievers, rerankers, generators, tool callers, memory) into graphs that handle RAG, conversational agents, multimodal processing, and tool-using workflows. The pipelines are cloud-agnostic, Kubernetes-friendly, and designed to be inspected and debugged rather than treated as a black box.

It is aimed at engineers who want a code-first alternative to LangChain or LlamaIndex with a stronger production bent. The core library is MIT-licensed and free; deepset sells Enterprise Support and a commercial deepset AI Platform on top with a visual pipeline builder, hosted deployment, and data workflows. Pricing for the commercial tiers is gated behind sales.

Integrations are broad: OpenAI, Anthropic, Mistral, Hugging Face, Cohere on the model side, and Weaviate, Pinecone, Elasticsearch, Qdrant, pgvector and others on the storage side. Install is `pip install haystack-ai`. The trade-off versus higher-level tools is that you assemble more of the plumbing yourself, but you also keep control of it.

Editor's take

Haystack is one of the more grown-up open-source RAG frameworks, with a clear bias toward shipping rather than demoing. If you've outgrown a notebook prototype and want pipelines you can serialize, version, and deploy on your own infra, it's a strong default choice next to LangChain and LlamaIndex.

— The AI Tool Bible editorial team