What is Haystack?
Haystack is an open-source framework developed by deepset for building production-ready retrieval-augmented generation (RAG) applications and semantic search systems. It provides a comprehensive pipeline-based architecture for connecting various components like document stores, retrievers, readers, and generators, with a focus on flexibility, customization, and production deployment requirements.
The framework uses a pipeline paradigm where data flows through interconnected nodes, each performing specific functions like document preprocessing, embedding generation, retrieval, answer extraction, or response generation. Haystack supports multiple backend options for each component type, allowing developers to mix and match different retriever algorithms (sparse, dense, hybrid), document stores (Elasticsearch, OpenSearch, Qdrant, etc.), and language models. This modularity enables experimentation and optimization for specific use cases.
Haystack distinguishes itself through its production-oriented features including evaluation frameworks for measuring pipeline performance, REST API generation for deploying pipelines as services, and extensive documentation and examples. While similar in scope to LangChain and LlamaIndex, Haystack emphasizes enterprise-grade robustness and has strong roots in the information retrieval community. It's particularly popular for building semantic search engines, question-answering systems, and document analysis applications.