Haystack

Haystack is an open-source framework by deepset that helps you build powerful, production-ready question-answering systems, RAG (Retrieval-Augmented Generation) pipelines, and LLM apps — using your own data.

It’s one of the most mature frameworks for building search and GenAI workflows with custom documents, embeddings, and language models.


🧠 What Is Haystack?

Haystack connects documents + LLMs to help users:

  • Ask natural language questions

  • Retrieve the right content from their data

  • Generate accurate, explainable answers

It supports both traditional keyword search and vector-based semantic search, making it flexible for all use cases.


🔑 Key Features

Feature
Description

RAG Pipelines

Connect retrievers + LLMs in multi-step pipelines

Modular Components

Plug-and-play building blocks for retrieval, generation, summarization

Flexible Backends

Supports FAISS, Weaviate, OpenSearch, Elasticsearch

Multi-Model Support

Use OpenAI, Cohere, Hugging Face, local models

Document Store

Save and search your own PDFs, texts, and websites

REST API + UI

Easy to deploy as a search backend or chatbot engine


🧪 Example Use Case

Want to build an internal chatbot that answers HR policy questions?

With Haystack, you can:

  1. Upload your HR docs to a document store

  2. Use a retriever to find relevant chunks

  3. Use an LLM (like OpenAI or Cohere) to answer clearly

  4. Wrap it in a chatbot UI or API


🧰 Developer-Friendly Features

  • Built-in Streamlit app for UI testing

  • Pipeline orchestration and visual flow

  • Supports feedback loops to fine-tune performance

  • Can be integrated with LangChain, LlamaIndex, FastAPI


📦 Ideal For

  • Enterprise RAG systems

  • Chat-with-your-data apps

  • Custom search engines

  • Building QA over PDFs, databases, websites


🧠 Summary

  • Haystack = Powerful framework for building LLM pipelines over your own data

  • Open-source, production-ready, and developer-friendly

  • Great for teams building custom GenAI apps with control, transparency, and flexibility


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