Build RAG Chatbot with Haystack, Haystack In-memory store, Cohere Command R+, and STACKIT e5-mistral-7b-instruct

Introduction to RAG

Retrieval-Augmented Generation (RAG) is a game-changer for GenAI applications, especially in conversational AI. It combines the power of pre-trained large language models (LLMs) like OpenAI’s GPT with external knowledge sources stored in vector databases such as Milvus and Zilliz Cloud, allowing for more accurate, contextually relevant, and up-to-date response generation. A RAG pipeline usually consists of four basic components: a vector database, an embedding model, an LLM, and a framework.

Key Components We'll Use for This RAG Chatbot

This tutorial shows you how to build a simple RAG chatbot in Python using the following components:

Haystack: An open-source Python framework designed for building production-ready NLP applications, particularly question answering and semantic search systems. Haystack excels at retrieving information from large document collections through its modular architecture that combines retrieval and reader components. Ideal for developers creating search applications, chatbots, and knowledge management systems that require efficient document processing and accurate information extraction from unstructured text.
Haystack in-memory store: a very simple, in-memory document store with no extra services or dependencies. It is great for experimenting with Haystack, and we do not recommend using it for production. If you want a much more scalable solution for your apps or even enterprise projects, we recommend using Zilliz Cloud, which is a fully managed vector database service built on the open-source Milvusand offers a free tier supporting up to 1 million vectors.)
Cohere Command R+: A state-of-the-art enterprise-focused LLM optimized for high-efficiency Retrieval-Augmented Generation (RAG) and tool use, designed to automate complex workflows. Strengths include multilingual support, scalability, and robust accuracy for enterprise-grade applications. Ideal for automating customer support, data analysis, and knowledge-intensive tasks while ensuring secure, reliable collaboration between AI and human teams.
STACKIT e5-mistral-7b-instruct: A 7B-parameter language model optimized for instruction-based tasks, delivering efficient, context-aware responses. Excels in natural language understanding, scalability, and low-latency performance. Ideal for enterprise automation, customer support, technical documentation, and generating structured outputs from complex prompts. Combines precision with adaptability for business-critical AI applications.

By the end of this tutorial, you’ll have a functional chatbot capable of answering questions based on a custom knowledge base.

Note: Since we may use proprietary models in our tutorials, make sure you have the required API key beforehand.

Step 1: Install and Set Up Haystack

import os
import requests

from haystack import Pipeline
from haystack.components.converters import MarkdownToDocument

from haystack.components.preprocessors import DocumentSplitter
from haystack.components.writers import DocumentWriter

Step 2: Install and Set Up Cohere Command R+

To use Cohere models with Haystack for a RAG pipeline, you need to get a Cohere API Key first. You can write this key in:

The api_key init parameter using Secret API
The COHERE_API_KEY environment variable (recommended)

Now, let's install and set up the Cohere model.

pip install cohere-haystack

from haystack_integrations.components.generators.cohere import CohereGenerator

generator = CohereGenerator(model="command-r-plus")

Step 3: Install and Set Up STACKIT e5-mistral-7b-instruct

pip install stackit-haystack

from haystack_integrations.components.embedders.stackit import STACKITTextEmbedder
from haystack_integrations.components.embedders.stackit import STACKITDocumentEmbedder

text_embedder = STACKITTextEmbedder(model="intfloat/e5-mistral-7b-instruct")
document_embedder = STACKITDocumentEmbedder(model="intfloat/e5-mistral-7b-instruct")

Step 4: Install and Set Up Haystack In-memory store

from haystack.document_stores.in_memory import InMemoryDocumentStore
from haystack.components.retrievers import InMemoryEmbeddingRetriever

document_store = InMemoryDocumentStore()
retriever=InMemoryEmbeddingRetriever(document_store=document_store))

Step 5: Build a RAG Chatbot

Now that you’ve set up all components, let’s start to build a simple chatbot. We’ll use the Milvus introduction doc as a private knowledge base. You can replace it your own dataset to customize your RAG chatbot.

url = 'https://raw.githubusercontent.com/milvus-io/milvus-docs/refs/heads/v2.5.x/site/en/about/overview.md'
example_file = 'example_file.md'
response = requests.get(url)
with open(example_file, 'wb') as f:
    f.write(response.content)
file_paths = [example_file]  # You can replace it with your own file paths.

indexing_pipeline = Pipeline()
indexing_pipeline.add_component("converter", MarkdownToDocument())
indexing_pipeline.add_component("splitter", DocumentSplitter(split_by="sentence", split_length=2))
indexing_pipeline.add_component("embedder", document_embedder)
indexing_pipeline.add_component("writer", DocumentWriter(document_store))
indexing_pipeline.connect("converter", "splitter")
indexing_pipeline.connect("splitter", "embedder")
indexing_pipeline.connect("embedder", "writer")
indexing_pipeline.run({"converter": {"sources": file_paths}})

# print("Number of documents:", document_store.count_documents())
  
question = "What is Milvus?"  # You can replace it with your own question.

retrieval_pipeline = Pipeline()
retrieval_pipeline.add_component("embedder", text_embedder)
retrieval_pipeline.add_component("retriever", retriever)
retrieval_pipeline.connect("embedder", "retriever")

retrieval_results = retrieval_pipeline.run({"embedder": {"text": question}})

# for doc in retrieval_results["retriever"]["documents"]:
#     print(doc.content)
#     print("-" * 10)

from haystack.utils import Secret
from haystack.components.builders import PromptBuilder

retriever=InMemoryEmbeddingRetriever(document_store=document_store) 
 text_embedder = STACKITTextEmbedder(model="intfloat/e5-mistral-7b-instruct")

prompt_template = """Answer the following query based on the provided context. If the context does
                     not include an answer, reply with 'I don't know'.\n
                     Query: {{query}}
                     Documents:
                     {% for doc in documents %}
                        {{ doc.content }}
                     {% endfor %}
                     Answer: 
                  """

rag_pipeline = Pipeline()
rag_pipeline.add_component("text_embedder", text_embedder)
rag_pipeline.add_component("retriever", retriever)
rag_pipeline.add_component("prompt_builder", PromptBuilder(template=prompt_template))
rag_pipeline.add_component("generator", generator)
rag_pipeline.connect("text_embedder.embedding", "retriever.query_embedding")
rag_pipeline.connect("retriever.documents", "prompt_builder.documents")
rag_pipeline.connect("prompt_builder", "generator")

results = rag_pipeline.run({"text_embedder": {"text": question}, "prompt_builder": {"query": question},})
print('RAG answer:\n', results["generator"]["replies"][0])

Optimization Tips

As you build your RAG system, optimization is key to ensuring peak performance and efficiency. While setting up the components is an essential first step, fine-tuning each one will help you create a solution that works even better and scales seamlessly. In this section, we’ll share some practical tips for optimizing all these components, giving you the edge to build smarter, faster, and more responsive RAG applications.

Haystack optimization tips

To optimize Haystack in a RAG setup, ensure you use an efficient retriever like FAISS or Milvus for scalable and fast similarity searches. Fine-tune your document store settings, such as indexing strategies and storage backends, to balance speed and accuracy. Use batch processing for embedding generation to reduce latency and optimize API calls. Leverage Haystack's pipeline caching to avoid redundant computations, especially for frequently queried documents. Tune your reader model by selecting a lightweight yet accurate transformer-based model like DistilBERT to speed up response times. Implement query rewriting or filtering techniques to enhance retrieval quality, ensuring the most relevant documents are retrieved for generation. Finally, monitor system performance with Haystack’s built-in evaluation tools to iteratively refine your setup based on real-world query performance.

Haystack in-memory store optimization tips

Haystack in-memory store is just a very simple, in-memory document store with no extra services or dependencies. We recommend that you just experiment it with RAG pipeline within your Haystack framework, and we do not recommend using it for production. If you want a much more scalable solution for your apps or even enterprise projects, we recommend using Zilliz Cloud, which is a fully managed vector database service built on the open-source Milvusand offers a free tier supporting up to 1 million vectors

Cohere Command R+ optimization tips

To optimize Cohere Command R+ in a RAG setup, preprocess input queries by chunking large texts and filtering irrelevant context to reduce noise. Use retrieval-friendly parameters like temperature=0.3 for focused responses and max_tokens=512 to balance detail and conciseness. Fine-tune document retrieval with semantic reranking and metadata filtering to prioritize high-relevance sources. Enable confidence_score to validate output reliability, and cache frequent queries to reduce latency. Monitor token usage and response quality to iteratively adjust retrieval thresholds and generation settings for cost-performance balance.

STACKIT e5-mistral-7b-instruct optimization tips

To optimize STACKIT e5-mistral-7b-instruct in RAG, ensure input context is well-structured with clear document chunks (≤512 tokens) and metadata for precise retrieval. Use dynamic temperature and top-p sampling to balance creativity and relevance. Fine-tune retrieval thresholds to minimize irrelevant context injection. Batch process queries for GPU efficiency, and enable FlashAttention for faster inference. Precompute embeddings for static data to reduce latency. Regularly evaluate retrieval accuracy and model outputs via metrics like Hit Rate and ROUGE, adjusting prompts and chunk sizes iteratively.

By implementing these tips across your components, you'll be able to enhance the performance and functionality of your RAG system, ensuring it’s optimized for both speed and accuracy. Keep testing, iterating, and refining your setup to stay ahead in the ever-evolving world of AI development.

RAG Cost Calculator: A Free Tool to Calculate Your Cost in Seconds

Estimating the cost of a Retrieval-Augmented Generation (RAG) pipeline involves analyzing expenses across vector storage, compute resources, and API usage. Key cost drivers include vector database queries, embedding generation, and LLM inference.

RAG Cost Calculator is a free tool that quickly estimates the cost of building a RAG pipeline, including chunking, embedding, vector storage/search, and LLM generation. It also helps you identify cost-saving opportunities and achieve up to 10x cost reduction on vector databases with the serverless option.

Calculate your RAG cost now.

Calculate your RAG cost

What Have You Learned?

Wow, you’ve just unlocked the power to build your own RAG system from scratch! By diving into this tutorial, you’ve learned how to seamlessly weave together four key components into a cohesive, intelligent pipeline. First, Haystack acted as your trusty framework, orchestrating the entire flow—like a conductor guiding an orchestra—so you could focus on connecting the dots without getting lost in the weeds. Then, the Haystack In-memory Store stepped in as your lightning-fast vector database, storing and retrieving embeddings with ease, ensuring your system stays nimble even when handling large datasets. The Cohere Command R+ model blew you away with its ability to generate human-like, context-aware responses, transforming raw data into meaningful answers. And let’s not forget the STACKIT e5-mistral-7b-instruct embedding model, which turned your text into rich numerical representations, making similarity searches accurate and efficient. You even got hands-on with practical steps like data ingestion, chunking, and retrieval, seeing firsthand how these pieces fit together to create a system that doesn’t just answer questions—it understands them.

But wait, there’s more! The tutorial didn’t just stop at the basics. You discovered optimization tricks like tweaking chunk sizes and balancing speed-versus-cost trade-offs, ensuring your RAG pipeline runs smoothly without breaking the bank. And that free RAG cost calculator? A game-changer for planning projects smartly! Now you’re equipped not just to build, but to innovate—experimenting with different models, refining retrieval strategies, or even adding domain-specific tweaks. Imagine the possibilities: chatbots that feel almost human, research tools that surface insights in seconds, or personalized recommendation engines. The future of AI-powered applications is literally at your fingertips. So what are you waiting for? Grab your code editor, fire up those models, and start crafting something extraordinary. Your journey into RAG has just begun, and the next breakthrough could be your creation. Let’s build, optimize, and revolutionize—one query at a time! 🚀

Further Resources

🌟 In addition to this RAG tutorial, unleash your full potential with these incredible resources to level up your RAG skills.

How to Build a Multimodal RAG | Documentation
How to Enhance the Performance of Your RAG Pipeline
Graph RAG with Milvus | Documentation
How to Evaluate RAG Applications - Zilliz Learn
Generative AI Resource Hub | Zilliz

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