Build a RAG pipeline from scratch — the actually simple version
Originally published on aiunplugged.in — cross-posting for the Dev.to community. Every RAG tutorial online starts with LangChain, LlamaIndex, or a hosted vector database signup. None of that is necessary to understand what a RAG pipeline actually is. This walkthrough builds one in a single Python file with three libraries — no framework, no cloud accounts, no config files. What RAG actually is…
The article explains how to build a Retrieval-Augmented Generation (RAG) pipeline using only three libraries in Python, without any frameworks, cloud accounts, or configuration files. Retrieval-Augmented Generation is a technique where an LLM answers a question using text pulled from a private document store at query time, rather than relying on the model's pre-existing knowledge.
RAG is useful when source data changes frequently, is private, or is large, and requires citing specific passages. The article outlines four steps in a RAG system: chunking the source documents, embedding the chunks, storing the chunks and embeddings in a vector database, and finally retrieving and generating the answer. The article provides a step-by-step guide on setting up the required libraries, chunking the documents, embedding them, storing them in a Chroma vector database, and finally retrieving and generating the answer using the Claude API.
The example uses a list of short product documentation snippets as the source material, and demonstrates how to chunk the text into smaller passages, embed them using the sentence-transformers library, and store them in a local Chroma vector database. Finally, the article shows how to retrieve the closest chunks to a user's query and generate an answer using the Claude API.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.