Haystack

Haystack, built by deepset, is a framework specifically aimed at retrieval-augmented generation and semantic search pipelines — connecting document stores, retrievers, and LLMs into a pipeline that can answer questions grounded in a specific knowledge base rather than the model’s general training data.

Compared to more general-purpose agent frameworks, Haystack leans into production concerns from the start: pipeline components are composable and swappable, evaluation tooling is built in, and it’s designed to be deployed as a real backend service rather than just prototyped in a notebook.