Amazon OpenSearch Vector Search Explained for RAG Systems

In this article, we will understand how vector search works in Amazon OpenSearch and how to use it as the retrieval layer in a retrieval-augmented generation (RAG) system. The article is meant for software engineers. We will not stop at theory. We will build a small, working example that you can run on your own machine and follow along step by step.

By the end, you will have a small document search service that takes a user question, finds the most relevant text using vector similarity, and prepares the context that you can pass to a language model.