RAG Explained: How to Build AI That Knows Your Data

Jun 15, 2024

RAG Explained: How to Build AI That Knows Your Data

ChatGPT is impressive. It can write code, explain quantum physics, and compose poetry that doesn't completely suck.

But it has no idea what's in your company's internal documentation. It doesn't know your product specifications. It can't answer questions about your customer data. And when you ask it anyway, it confidently makes stuff up.

This is the fundamental problem with large language models: they know everything in general and nothing about you specifically.

Enter RAG: Retrieval-Augmented Generation. It's the technique that lets you give AI a library card to your own knowledge base. Instead of hallucinating answers, it actually looks stuff up.

If you've ever thought "I wish ChatGPT knew about MY data," this is how you make that happen. Let me show you what RAG is, when to use it, and how to build your first system in about 100 lines of code.

No PhD required. No buzzword nonsense. Just practical AI that actually works.

What the Hell is RAG?

Let me explain RAG with an analogy:

Traditional LLM: A really smart person with an amazing memory who refuses to admit when they don't know something. Ask them anything, and they'll give you a confident answer. Sometimes it's right. Sometimes it's completely made up. You can't tell the difference.

RAG System: That same smart person, but now they have a library card. When you ask them something they don't know, they go look it up, read the relevant pages, and then answer based on what they found. They can even cite their sources.

That's RAG. It's not magic. It's just giving LLMs the ability to look stuff up before answering.

Here's the problem RAG solves:

You ask ChatGPT: "What's our refund policy for enterprise customers?"

ChatGPT responds: "Based on typical enterprise SaaS practices, your refund policy probably allows 30-day returns with..."

WRONG. It just hallucinated your entire policy.

With RAG:

  1. Your question gets converted to a search query

  2. System searches your company docs for "refund policy enterprise"

  3. Finds the actual policy document

  4. Feeds it to the LLM along with your question

  5. LLM answers based on YOUR real policy, not made-up nonsense

The difference? One is guessing. The other is reading and then answering.

Real-world example: Customer support chatbot

Without RAG:

  • "How do I reset my password?" → Generic answer that might not match your actual process

  • "What's included in the Pro plan?" → Hallucinated feature list

  • Result: Angry customers, confused support team

With RAG:

  • System searches your actual documentation

  • Returns accurate, sourced answers

  • Cites which doc it used

  • Result: Happy customers, less support load

The magic of RAG: You update your docs, and the AI automatically knows the new information. No retraining. No fine-tuning. Just update the knowledge base and you're done.

The Three Components of RAG

Building a RAG system has three main pieces. None of them are particularly complicated, which is good news.

1. Document Ingestion & Embedding

First, you need to turn your documents into something searchable.

The process:

Step 1: Break documents into chunks

You can't feed an entire 500-page manual to an LLM. Context windows have limits. So you split documents into smaller pieces (usually 500-1000 characters each).


Step 2: Convert chunks to embeddings

This is where it gets interesting. Each chunk gets converted into a vector—basically a list of numbers that represents the meaning of the text.

Similar meaning = similar numbers.

"refund policy" → [0.23, -0.45, 0.67, ..., 0.12]  (1536 numbers)
"return process" → [0.24, -0.43, 0.65, ..., 0.15]  (very similar!)
"pizza toppings" → [-0.87, 0.34, -0.12, ..., 0.91]

The magic: You can now search by meaning, not just keywords. "How do I get my money back?" will find your refund policy even though the words don't match exactly.

2. Vector Storage

Now you need somewhere to store these embeddings so you can search them later.

Vector databases are designed for this. They can:

  • Store millions of vectors efficiently

  • Search them fast (milliseconds)

  • Find the most similar vectors to your query

Popular options:

  • Pinecone - Cloud-hosted, easy, costs money

  • Weaviate - Open-source, self-hosted, powerful

  • pgvector - PostgreSQL extension (my favorite for small-to-medium projects)

  • FAISS - Facebook's library, great for local development

  • Chroma - Simple, embedded, perfect for prototypes

For your first RAG system, use Chroma or FAISS. They're free and work out of the box.

How retrieval works:

When someone asks "What's the refund policy?":

  1. Question gets embedded: [0.25, -0.44, 0.66, ..., 0.13]

  2. Vector database finds chunks with similar embeddings

  3. Returns top 3-5 most relevant chunks

  4. These chunks become context for the LLM

It's like Google, but for meaning instead of keywords.

3. Retrieval + Generation

This is where RAG becomes useful.

The flow:

  1. User asks: "How long does shipping take?"

  2. System embeds the question

  3. Searches vector DB for relevant chunks

  4. Finds: "Standard shipping: 5-7 business days. Express: 2-3 days..."

  5. Builds a prompt: "Based on this information: [chunks], answer: [question]"

  6. LLM generates answer using YOUR data

  7. Returns answer with sources

Why this is better than raw LLM:

  • ✅ Answers based on facts, not hallucinations

  • ✅ Can cite sources

  • ✅ Updates when docs update (no retraining)

  • ✅ Works with private/proprietary data

  • ✅ Much cheaper than fine-tuning

The catch: You need good documents. Garbage in, garbage out. RAG won't magically make bad documentation good.

RAG vs Fine-Tuning vs Prompt Engineering

"Should I use RAG, fine-tune, or just write better prompts?"

Great question. Here's when to use what:

Approach

When to Use

Cost

Speed

Best For

Prompt Engineering

Knowledge fits in prompt

Free

Instant

Simple rules, small knowledge

RAG

Large/changing knowledge base

Low-Med

Fast

Dynamic docs, Q&A systems

Fine-Tuning

Need specific style/behavior

High

Slow

Domain expertise, writing style

Examples:

Use Prompt Engineering when:

  • "Always respond in a professional tone"

  • "Format output as JSON"

  • "Never use contractions"

  • Simple rules that fit in system prompt

Use RAG when:

  • "Answer based on our 500 product manuals"

  • "Search through 10,000 customer support tickets"

  • "Query our internal documentation"

  • Large knowledge that changes frequently

Use Fine-Tuning when:

  • "Write legal contracts in our firm's specific style"

  • "Generate code following our company conventions"

  • "Diagnose medical conditions using domain knowledge"

  • Need behavior change, not just knowledge access

The truth nobody tells you: You'll probably use all three together.

  • Fine-tune for style and domain expertise

  • Add RAG for knowledge retrieval

  • Use prompts for formatting and rules

But if you're starting? Start with RAG. It's easier, cheaper, and more flexible than fine-tuning.

Building Your First RAG System

Let's build a simple document Q&A system. Full working code. No hand-waving.

What we're building:

  • Load documents from a folder

  • Make them searchable

  • Ask questions, get answers with sources

Step 1: Install Dependencies

What these do:

  • langchain - Framework for building LLM apps

  • openai - Access to GPT models

  • chromadb - Local vector database

  • tiktoken - Token counting (useful for chunking)

Step 2: Load Your Documents

from langchain.document_loaders import TextLoader, DirectoryLoader
from langchain.text_splitter import RecursiveCharacterTextSplitter

# Load all .txt files from a directory
loader = DirectoryLoader(
    './docs',           # Your documents folder
    glob="**/*.txt",    # Load all .txt files
    loader_cls=TextLoader
)

documents = loader.load()
print(f"Loaded {len(documents)} documents")

# Split documents into chunks
text_splitter = RecursiveCharacterTextSplitter(
    chunk_size=1000,        # ~1000 characters per chunk
    chunk_overlap=200,      # 200 char overlap between chunks
    length_function=len,
    separators=["\n\n", "\n", " ", ""]  # Split on paragraphs first
)

chunks = text_splitter.split_documents(documents)
print(f"Created {len(chunks)} chunks")

Why chunking matters:

Imagine you have a 50-page product manual. You can't feed the whole thing to GPT every time someone asks a question. So you split it into chunks:

  • Chunk 1: Introduction section

  • Chunk 2: Setup instructions

  • Chunk 3: Troubleshooting

  • etc.

When someone asks "How do I set up?", you only retrieve the setup chunk, not the entire manual.

Why overlap?

If you split exactly at 1000 characters, you might cut a sentence in half. The overlap ensures you don't lose context at boundaries.

Step 3: Create Embeddings and Store in Vector DB

from langchain.embeddings import OpenAIEmbeddings
from langchain.vectorstores import Chroma
import os

# Set your OpenAI API key
os.environ["OPENAI_API_KEY"] = "your-api-key-here"

# Create embeddings (this costs money, but very little)
embeddings = OpenAIEmbeddings()

# Create vector database and store chunks
vectorstore = Chroma.from_documents(
    documents=chunks,
    embedding=embeddings,
    persist_directory="./chroma_db"  # Saves to disk
)

print("✅ Vector database created and saved!")

What just happened:

Each of your chunks got converted into a 1536-dimensional vector using OpenAI's embedding model. These vectors are now stored in Chroma, a local database.

Cost: Embedding 1000 chunks ≈ $0.01. Basically free.

Step 4: Build the Q&A Chain

from langchain.chains import RetrievalQA
from langchain.chat_models import ChatOpenAI

# Create the LLM (this is what generates answers)
llm = ChatOpenAI(
    model_name="gpt-4",
    temperature=0  # 0 = deterministic, 1 = creative
)

# Create the retrieval chain
qa_chain = RetrievalQA.from_chain_type(
    llm=llm,
    chain_type="stuff",  # Simple: stuff all chunks into prompt
    retriever=vectorstore.as_retriever(
        search_type="similarity",
        search_kwargs={"k": 3}  # Return top 3 most relevant chunks
    ),
    return_source_documents=True  # Show which docs were used
)

print("✅ RAG system ready!")

What's chain_type="stuff"?

It means "stuff all the retrieved chunks into the prompt." Simple and works for most cases.

Other options:

  • map_reduce - Summarize each chunk, then combine (for lots of chunks)

  • refine - Iteratively refine answer with each chunk (slower but better)

Start with "stuff." It works 90% of the time.

Step 5: Ask Questions!

# Ask a question
question = "What is our refund policy?"

result = qa_chain({"query": question})

# Print the answer
print("\n" + "="*50)
print(f"Question: {question}")
print("="*50)
print(f"\nAnswer: {result['result']}\n")

# Print sources
print("Sources:")
for i, doc in enumerate(result['source_documents'], 1):
    print(f"\n{i}. From: {doc.metadata['source']}")
    print(f"   Content preview: {doc.page_content[:200]}...")
print("="*50)

Sample output:


Boom. You just built RAG.

The system:

  1. Embedded your question

  2. Searched for relevant chunks

  3. Found your policy docs

  4. Fed them to GPT-4

  5. Got an accurate answer

  6. Cited its sources

Step 6: Make It Interactive

def ask_docs(question):
    """Simple function to query your documents"""
    result = qa_chain({"query": question})
    
    print(f"\n{'='*60}")
    print(f"Q: {question}")
    print(f"{'='*60}")
    print(f"\n{result['result']}\n")
    
    print("📚 Sources:")
    for i, doc in enumerate(result["source_documents"], 1):
        source = doc.metadata.get('source', 'Unknown')
        print(f"  {i}. {source}")
    print(f"{'='*60}\n")

# Try it out
ask_docs("What are your business hours?")
ask_docs("Do you offer international shipping?")
ask_docs("How do I return a product?")
ask_docs("What's included in the Pro plan?")

That's it. You now have a working RAG system that can answer questions about YOUR documents.

Common RAG Challenges (And How to Fix Them)

RAG isn't magic. You'll hit problems. Here's what to expect and how to solve them.

Challenge #1: Retrieval Quality Sucks

Problem: System returns irrelevant chunks. You ask about refunds, it gives you shipping info.

Why it happens:

  • Bad chunking (chunks are too big or too small)

  • Documents aren't well-organized

  • Query doesn't match document language

Solutions:

Better chunking:

# Instead of fixed 1000 chars, split semantically
from langchain.text_splitter import MarkdownTextSplitter

splitter = MarkdownTextSplitter(
    chunk_size=1000,
    chunk_overlap=200
)
# This respects markdown structure (headers, paragraphs)

Add metadata filtering:

# Tag chunks with metadata
for chunk in chunks:
    chunk.metadata['category'] = 'policy'
    chunk.metadata['department'] = 'customer_service'

# Search only relevant categories
retriever = vectorstore.as_retriever(
    search_kwargs={
        "k": 5,
        "filter": {"category": "policy"}  # Only search policies
    }
)

Use reranking:

# Retrieve 10 chunks, rerank to top 3
from langchain.retrievers import ContextualCompressionRetriever
from langchain.retrievers.document_compressors import LLMChainExtractor

compressor = LLMChainExtractor.from_llm(llm)
compression_retriever = ContextualCompressionRetriever(
    base_compressor=compressor,
    base_retriever=vectorstore.as_retriever(search_kwargs={"k": 10})
)
# Now only the most relevant 3 chunks get used

Challenge #2: Context Window Limitations

Problem: You retrieve 10 chunks of 1000 chars each = 10,000 chars. Your context window is only 8,000. Now what?

Solutions:

Retrieve fewer chunks:

# Quality over quantity
retriever = vectorstore.as_retriever(search_kwargs={"k": 3})

Use map-reduce for long docs:

from langchain.chains import RetrievalQA

qa_chain = RetrievalQA.from_chain_type(
    llm=llm,
    chain_type="map_reduce",  # Summarize each chunk first
    retriever=retriever
)

Upgrade to larger context models:

# GPT-4 Turbo has 128K context window
llm = ChatOpenAI(model_name="gpt-4-turbo", temperature=0)

Challenge #3: Slow Response Times

Problem: Users wait 5+ seconds for answers. That's unacceptable.

Why it's slow:

  • Embedding the query (200-500ms)

  • Searching vector DB (100-300ms)

  • LLM generation (2-4 seconds)

  • Total: 3-5 seconds

Solutions:

Cache common queries:

from functools import lru_cache

@lru_cache(maxsize=100)
def get_answer(question):
    return qa_chain({"query": question})

Use faster embedding models:

# Use smaller, faster models for embeddings
from langchain.embeddings import HuggingFaceEmbeddings

embeddings = HuggingFaceEmbeddings(
    model_name="all-MiniLM-L6-v2"  # Much faster, still good
)

Optimize vector database:

# Use HNSW index for faster search
vectorstore = Chroma.from_documents(
    documents=chunks,
    embedding=embeddings,
    collection_metadata={"hnsw:space": "cosine"}
)

Use streaming for better UX:

# Stream response word-by-word (feels faster)
from langchain.callbacks.streaming_stdout import StreamingStdOutCallbackHandler

llm = ChatOpenAI(
    model_name="gpt-4",
    streaming=True,
    callbacks=[StreamingStdOutCallbackHandler()]
)

Challenge #4: Hallucinations Still Happen

Problem: Even with RAG, the LLM sometimes makes stuff up.

Why: LLMs are creative. Sometimes too creative.

Solutions:

Lower temperature:

llm = ChatOpenAI(temperature=0)  # 0 = stick to facts

Explicit prompts:

from langchain.prompts import PromptTemplate

template = """You are a helpful assistant. Answer the question 
based ONLY on the following context. If the answer is not in 
the context, say "I don't have that information."

Context: {context}

Question: {question}

Answer:"""

prompt = PromptTemplate(template=template, input_variables=["context", "question"])

qa_chain = RetrievalQA.from_chain_type(
    llm=llm,
    chain_type="stuff",
    retriever=retriever,
    chain_type_kwargs={"prompt": prompt}
)

Add confidence scores:

# Ask LLM to rate its confidence
template = """Answer the question and rate your confidence (0-100%).

Context: {context}
Question: {question}

Answer: [your answer]
Confidence: [0-100]%
"""

# Then filter out low-confidence answers
if confidence < 70:
    return "I'm not confident enough to answer that."

Challenge #5: Cost Adds Up

Problem: Every query costs money. Embeddings + LLM calls = $$$.

Solutions:

Cache embeddings:

# Don't re-embed the same documents
vectorstore = Chroma(
    persist_directory="./chroma_db",
    embedding_function=embeddings
)
# Embeddings persist, you only pay once

Use open-source embeddings:

from sentence_transformers import SentenceTransformer

# Free, local, fast
model = SentenceTransformer('all-MiniLM-L6-v2')
embeddings = model.encode(texts)

Use GPT-3.5 for simple queries:

# Route by complexity
if is_simple_query(question):
    llm = ChatOpenAI(model="gpt-3.5-turbo")  # Cheaper
else:
    llm = ChatOpenAI(model="gpt-4")  # Better but pricier

Batch processing:

# Process multiple queries at once
questions = ["Q1", "Q2", "Q3"]
answers = [qa_chain({"query": q}) for q in questions]

When NOT to Use RAG

RAG is powerful, but it's not always the answer. Don't use it when:

1. Knowledge is Tiny and Static

Example: "Our company has 3 products with fixed prices"

Better solution: Just put it in the system prompt

system_prompt = """You are a sales assistant for Acme Corp.
We sell:
- Widget Pro: $99/month
- Widget Enterprise: $499/month  
- Widget Ultimate: $999/month

Answer questions about our products."""

No need for RAG. It's overkill.

2. You Need Real-Time Transactional Data

Example: "What's my current account balance?"

Better solution: Query the database directly with SQL or an API

RAG is for knowledge retrieval, not database queries. Use the right tool for the job.

3. You Need Guaranteed Accuracy

Example: Medical diagnoses, legal advice, financial calculations

Better solution: RAG can assist, but require human review

LLMs can still make mistakes even with RAG. For high-stakes decisions, humans need to be in the loop.

4. Documents Are Highly Structured

Example: Querying spreadsheets, database tables, structured forms

Better solution: Use SQL, Pandas, or structured query languages

# Don't use RAG for this
"What's the average sale price in Q3?"

# Use SQL instead
SELECT AVG(price) FROM sales WHERE quarter = 'Q3'

5. You're Just Starting

Example: MVP with 5 documents, unclear if users will even ask questions

Better solution: Start with simple prompts, add RAG later

Don't over-engineer V1. Build RAG when the pain of not having it becomes real.

The rule of thumb:

Use RAG when:

  • ✅ Knowledge base is large (100+ docs)

  • ✅ Content changes frequently

  • ✅ Users ask unpredictable questions

  • ✅ You need source attribution

  • ✅ You can't fit everything in a prompt

Real-World RAG Example: Customer Support Chatbot

Let's look at a concrete example.

The Problem:

Your company has:

  • 500 product documentation pages

  • 200 FAQ articles

  • 1,000 past support tickets

  • Docs updated weekly by product team

Support team answers the same questions repeatedly. Customers wait hours for responses. Hiring more support agents is expensive.

The RAG Solution:

import os
from langchain.document_loaders import DirectoryLoader
from langchain.embeddings import OpenAIEmbeddings
from langchain.vectorstores import Chroma
from langchain.chat_models import ChatOpenAI
from langchain.chains import RetrievalQA
from langchain.text_splitter import RecursiveCharacterTextSplitter

class SupportChatbot:
    def __init__(self, docs_path):
        # Load all documentation
        loader = DirectoryLoader(docs_path, glob="**/*.md")
        documents = loader.load()
        
        # Split into chunks
        splitter = RecursiveCharacterTextSplitter(
            chunk_size=1000,
            chunk_overlap=200
        )
        chunks = splitter.split_documents(documents)
        
        # Create embeddings and vector store
        embeddings = OpenAIEmbeddings()
        self.vectorstore = Chroma.from_documents(
            chunks,
            embeddings,
            persist_directory="./support_db"
        )
        
        # Create QA chain
        llm = ChatOpenAI(model="gpt-4", temperature=0)
        self.qa_chain = RetrievalQA.from_chain_type(
            llm=llm,
            retriever=self.vectorstore.as_retriever(
                search_kwargs={"k": 5}
            ),
            return_source_documents=True
        )
    
    def answer(self, question):
        """Answer a support question"""
        result = self.qa_chain({"query": question})
        
        return {
            "answer": result["result"],
            "sources": [
                doc.metadata["source"] 
                for doc in result["source_documents"]
            ],
            "confidence": self._calculate_confidence(result)
        }
    
    def _calculate_confidence(self, result):
        """Simple confidence calculation"""
        # If multiple sources agree, higher confidence
        unique_sources = len(set(
            doc.metadata["source"] 
            for doc in result["source_documents"]
        ))
        
        if unique_sources == 1:
            return "high"
        elif unique_sources <= 3:
            return "medium"
        else:
            return "low"

# Usage
chatbot = SupportChatbot('./support_docs')

# Customer asks question
response = chatbot.answer("How do I reset my password?")

print(f"Answer: {response['answer']}")
print(f"Sources: {', '.join(response['sources'])}")
print(f"Confidence: {response['confidence']}")

Results After Deployment:

  • 80% of questions answered automatically

    • "How do I reset password?" ✅

    • "What's the refund policy?" ✅

    • "How do I upgrade my plan?" ✅

  • 20% escalated to humans

    • Complex account issues

    • Billing disputes

    • Feature requests

  • Response time: <2 seconds (vs 2 hours with human-only)

  • Cost: ~$50/month for 1,000 queries

    • Embeddings: $5/month (one-time for new docs)

    • LLM calls: $45/month (at $0.045 per query)

  • Support team loves it

    • Handles repetitive questions

    • They focus on complex issues

    • Customers happier (instant responses)

The catch: You need good documentation. If your docs suck, RAG will just efficiently serve up sucky answers.

Advanced RAG Techniques (Teaser)

We've covered basic RAG. But there's more you can do:

Hybrid Search

  • Combine keyword search (BM25) + semantic search (embeddings)

  • Best of both worlds: exact matches + meaning

Reranking

  • Retrieve 20 chunks

  • Use a reranker model to pick best 3

  • Much better precision

Query Decomposition

  • Break "Compare Pro vs Enterprise features" into sub-questions

  • Answer each separately

  • Synthesize final answer

Hypothetical Document Embeddings (HyDE)

  • Generate a hypothetical answer to the question

  • Search for docs similar to that answer

  • Often finds better results than searching with the question

Agent-Based RAG

  • LLM decides when to retrieve

  • Can make multiple retrieval calls

  • Can use different knowledge sources

  • More flexible, more powerful

Multi-Modal RAG

  • Search images, videos, audio

  • Combine text + visual information

  • Future of RAG

These are advanced techniques. Master basic RAG first.

I'll cover these in detail in my "Advanced RAG Techniques" article (coming soon).

RAG Best Practices

After building several RAG systems, here's what actually matters:

1. Chunk Smartly

Don't:

  • Use fixed 1000-character splits that cut sentences in half

  • Make chunks too small (<300 chars) or too large (>1500 chars)

  • Ignore document structure

Do:

  • Split on semantic boundaries (paragraphs, sections)

  • Use 500-1000 characters for most cases

  • Add 150-200 char overlap

  • Respect document structure (headings, lists)

splitter = RecursiveCharacterTextSplitter(
    chunk_size=800,
    chunk_overlap=200,
    separators=["\n\n", "\n", ". ", " ", ""]
)

2. Add Metadata

Tag every chunk:

chunk.metadata = {
    "source": "product_manual.pdf",
    "page": 15,
    "section": "Troubleshooting",
    "date_updated": "2025-01-15",
    "author": "Support Team",
    "category": "technical"
}

Why: Enables filtering, improves relevance, helps debugging

3. Test Retrieval Quality First

Before building the full system:

# Test if you're getting relevant chunks
query = "How do I refund?"
docs = vectorstore.similarity_search(query, k=5)

print("Retrieved chunks:")
for i, doc in enumerate(docs, 1):
    print(f"\n{i}. {doc.page_content[:200]}")
    print(f"   From: {doc.metadata['source']}")

If retrieval sucks, the whole system sucks. Fix it before adding the LLM.

4. Monitor Everything

import time

def monitored_query(question):
    start = time.time()
    result = qa_chain({"query": question})
    latency = time.time() - start
    
    # Log metrics
    log_metric("query_latency", latency)
    log_metric("chunks_retrieved", len(result["source_documents"]))
    log_metric("tokens_used", count_tokens(result["result"]))
    
    return result

Track:

  • Query latency

  • Retrieval quality

  • Cost per query

  • User satisfaction (thumbs up/down)

5. Version Your Knowledge Base

# Tag when docs were indexed
vectorstore = Chroma.from_documents(
    chunks,
    embeddings,
    collection_metadata={
        "version": "2025-01-15",
        "source": "product_docs_v2.3"
    }
)

Why: You can rollback if new docs break things, A/B test different chunking strategies

6. Handle "I Don't Know" Gracefully

Force the LLM to admit uncertainty:

template = """Answer based on the context below. 
If the answer is not in the context, respond with:
"I don't have that information in my knowledge base."

Context: {context}
Question: {question}
Answer:"""

Better to say "I don't know" than to hallucinate confidently.

7. Start Simple, Iterate

V1: Basic RAG with LangChain + Chroma
V2: Add metadata filtering
V3: Improve chunking strategy
V4: Add reranking
V5: Implement hybrid search

Don't build V5 on day one. Ship V1, measure, iterate.

Conclusion

RAG isn't magic. It's a practical, proven way to make LLMs useful for your specific data.

The core idea:

  1. Store your documents as searchable vectors

  2. Find relevant chunks for each query

  3. Feed chunks + query to LLM for answer

It's that simple.

When to use RAG:

  • Large, changing knowledge bases (100+ docs)

  • Need accurate, sourced answers

  • Can't fine-tune constantly

  • Private/proprietary data

When NOT to use RAG:

  • Tiny knowledge base (use prompts)

  • Real-time transactional data (use APIs)

  • Guaranteed accuracy required (add human review)

Your next steps:

  1. Build a simple RAG system

    • Pick 10-20 docs

    • Use the code from this article

    • Test with real questions

  2. Test retrieval quality

    • Are you getting relevant chunks?

    • Iterate on chunking strategy

  3. Add it to a real project

    • Internal doc search

    • Customer support chatbot

    • Product Q&A

  4. Monitor and improve

    • Track what works

    • Fix what doesn't

    • Iterate based on user feedback

RAG won't solve every problem. But for making AI understand your domain? It's the best tool we have.

Want to go deeper?

Check out my other articles:

  • "Advanced RAG: Chunking Strategies That Actually Work" (coming soon)

  • "Building Production RAG with pgvector" (coming soon)

  • "5 Things I Wish I Knew Before Building My First MLOps Pipeline" (live now)

Questions? Let's connect:

Now go build something cool. And when your RAG system hallucinates (it will), remember: even Google gets it wrong sometimes.

About the Author

Jonathan Sodeke is a Data Engineer and ML Engineer who builds AI systems that actually work in production, not just in demos. He specializes in RAG, MLOps, and making LLMs useful for real-world applications.

When he's not debugging vector databases at 2am, he's writing about the practical reality of building AI systems and teaching others to navigate the hype.

Portfolio: jonathansodeke.framer.website
GitHub: github.com/Shodexco
LinkedIn: https://www.linkedin.com/in/jonathan-sodeke/


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© Jonathan Sodeke 2025

© Jonathan Sodeke 2025

© Jonathan Sodeke 2025

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