> ## Documentation Index
> Fetch the complete documentation index at: https://io.net/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

> The R2R Indices API manages vector index structures that enable high-speed similarity search across chunks. It supports multiple index methods, configurable similarity measures, and concurrent building for optimized RAG retrieval performance.

An **Index** in R2R represents a **vector index structure** designed to optimize **similarity search** operations across document chunks. Indices are a core component of R2R’s **Retrieval-Augmented Generation (RAG)** architecture, enabling fast and scalable semantic retrieval.

By organizing vector embeddings efficiently, indices make it possible to perform **high-performance vector searches** across large datasets using different similarity metrics and indexing strategies.

### Key Capabilities

Indices in R2R provide:

* **Fast similarity search** for vector-based retrieval.
* **Multiple index methods**, including **HNSW** (Hierarchical Navigable Small World) and **IVF-Flat**.
* **Configurable similarity measures** such as cosine similarity or inner product.
* **Concurrent index building** to improve throughput and scalability.
* **Performance optimization** for large-scale vector operations.

## API Endpoints

| Method | Endpoint                                                                                | Description                                              |
| ------ | --------------------------------------------------------------------------------------- | -------------------------------------------------------- |
| GET    | [/indices](/reference/rag/indices/list-all-indices)                                     | List available indices with pagination.                  |
| GET    | [/indices/{table_name}/{index_name}](/reference/rag/indices/get-specific-index-details) | Retrieve details and configuration for a specific index. |
| DELETE | [/indices/{table_name}/{index_name}](/reference/rag/indices/delete-an-index)            | Delete an existing index.                                |