Approximate Nearest Neighbors in C++/Python optimized for memory usage and loading/saving to disk

mlpack: a fast, header-only C++ machine learning library

The AI-native database built for LLM applications, providing incredibly fast hybrid search of dense vector, sparse vector, tensor (multi-vector), and full-text

Fast Open-Source Search & Clustering engine × for Vectors & 🔜 Strings × in C++, C, Python, JavaScript, Rust, Java, Objective-C, Swift, C#, GoLang, and Wolfram 🔍

🛰️ An approximate nearest-neighbor search library for Python and Java with a focus on ease of use, simplicity, and deployability.

Nearest Neighbor Search with Neighborhood Graph and Tree for High-dimensional Data

Fast and lightweight header-only C++ library (with Python bindings) for approximate nearest neighbor search

Fast and memory-efficient ANN with a subset-search functionality

hnswlib-node provides Node.js bindings for Hnswlib

[SIGMOD 2024] RaBitQ: Quantizing High-Dimensional Vectors with a Theoretical Error Bound for Approximate Nearest Neighbor Search

SONG: Approximate Nearest Neighbor Search on GPU. SONG is a graph-based approximate nearest neighbor search toolbox.

PQ Fast Scan

A header-only C++ library for k nearest neighbor search with Eigen3.

Fast search algorithm for product-quantized codes via hash-tables

[SIGMOD 2023] High-Dimensional Approximate Nearest Neighbor Search: with Reliable and Efficient Distance Comparison Operations

A framework for building (and incrementally growing) graph-based data structures used in hierarchical or DAG-structured clustering and nearest neighbor search

Approximate Nearest Neighbor search using reduced-rank regression, with extremely fast queries, tiny memory usage, and rapid indexing on modern vector embeddings.

C++ implementation of KDTree & kNN classification on MNIST

Rcpp bindings for the approximate nearest neighbors library hnswlib

annoy-rb provides Ruby bindings for the Annoy (Approximate Nearest Neighbors Oh Yeah).