Haystack

Haystack is an open-source AI orchestration framework built by deepset for production-grade LLM applications. Its pipeline-centric, modular architecture treats each component (retriever, reader, generator) as a node in a directed acyclic graph, giving you explicit control over retrieval, routing, memory, and generation. It is purpose-built for RAG, with support for a multitude of retrieval and generation strategies out of the box. Integrations cover OpenAI, Anthropic, Mistral, Cohere, Hugging Face, Azure OpenAI, AWS Bedrock, and local models. The enterprise platform adds observability, collaboration, governance, and access controls, available as managed cloud or self-hosted. For teams building RAG applications who find LangChain too opinionated and want a clean pipeline abstraction, Haystack is the strongest alternative.