Haystack

Founded by Milos Rusic in 2019

Build retrieval augmented generation pipelines and autonomous agents using modular open source components

Pricing model

Free

Rating

★ People love it

Time to value

Quick Setup (< 1 hour)

You can use Haystack to build custom search pipelines, question answering systems, and multi-step agents. It provides modular components that connect large language models with vector databases, document stores, and external data sources. You can assemble complex workflows with branching logic, evaluate model responses, and inspect every step of the decision process. It works with models from providers like OpenAI and Mistral, as well as open source models from Hugging Face, making it easier to build, deploy, and test production agent systems reliably.

What Haystack does

Connect language models to document storesRetrieve relevant context for user questionsExecute multi-step tool calls within agent workflowsDebug intermediate reasoning steps in complex pipelinesFormat prompts dynamically with template variablesEvaluate accuracy of generated answers against ground truthBuild modular retrieval-augmented generation pipelinesCreate agents with standardized tool calling and branching flowsInspect and debug intermediate steps and decisions across pipelinesSerialize pipelines for export and deployment across environmentsIntegrate directly with multiple vector databases and search enginesSupport multimodal processing including image and audio inputsTemplate prompt generation using Jinja2 syntax