Haystack

Open-Source LLM Application Framework

Haystack is an open-source AI orchestration framework developed by deepset for building production-ready LLM applications, RAG systems, and semantic search pipelines. It provides the building blocks — document stores, retrievers, readers, and generators — needed to construct sophisticated AI applications that combine retrieval and generation in robust, maintainable pipelines.

Pipeline-Based Architecture

Haystack's core abstraction is the pipeline: a directed graph of components that process data from input to output. This pipeline architecture makes it straightforward to build complex AI workflows that combine document retrieval, query expansion, reranking, and LLM generation in a configurable, testable way. Pipelines can be serialized to YAML for version control and easy deployment.

• Modular pipeline components for RAG and search systems
• Supports 10+ vector databases and document stores
• Integration with all major LLM providers
• Built-in evaluation tools for pipeline quality testing
• Active open-source community with frequent releases

Production-Ready AI Applications

Haystack is used by enterprise teams building document search systems, question answering applications, and AI-powered knowledge bases. Its production-readiness features — logging, tracing, evaluation, and scalability — distinguish it from experimental frameworks and make it suitable for deployment in critical business applications.