Kabosu provides Ruby bindings for sudachi.rs, a Rust implementation of the Sudachi Japanese morphological analyzer.

kobako provides an in-process Wasm sandbox (wasmtime + mruby) with a MessagePack-based host/guest RPC, allowing Ruby applications to execute untrusted mruby scripts under capability-based Service injection.

Kreuzberg is a high-performance document intelligence library with a Rust core and native Ruby bindings via Magnus. Extract text, metadata, and structured data from 75+ file formats including PDF, DOCX, PPTX, XLSX, HTML, RTF, images (with OCR), email, archives, and more. Features async/sync APIs, text chunking, language detection, and keyword extraction.

Lancelot provides a Ruby-native interface to Lance, enabling efficient storage and search of multimodal data including text, vectors, and more.

Levenshtein string distance algorithm in Rust.

LexerKit is a high performance lexer toolkit for Ruby

Provides a mechanism for ruby applications to use codeowners-rs.

A library for processing standard bibliographic numbers

Native Ruby bindings for libSQL database, built with Rust (magnus + libsql crate)

lightningcss_rb wraps the LightningCSS Rust library via a native extension, exposing CSS parsing (to an AST), transformation, and minification to Ruby.

Native Ruby bindings for the Lingua Rust library, bringing highly accurate language detection for short text and mixed-language text to Ruby, with confidence scores and ISO 639-1/639-3 language codes.

Ruby (Rust) gem wrapper around Lingua library.

Ruby bindings for LiteParse — an open-source document parser that extracts text with spatial layout information, bounding boxes, OCR support, and more.

Ruby bindings for the Lora in-memory graph database. Exposes the embedded Rust engine as a native extension via Magnus/rb-sys, so queries run in-process without a separate server.

Ruby bindings (via Rust/magnus) for lz4rip, a pure-Rust LZ4 implementation. Block-format and frame-format compress/decompress with optional dictionary support and COVER-based dictionary training. Ractor-safe.

magicprotorb lets you `require "magicprotorb/foo/bar_pb"` and have foo/bar.proto compiled to descriptors and registered at require time. The dotted require path mirrors the canonical proto path 1:1, so the require name, the file location, and the descriptor name can never drift apart. A small Rust extension (built on the pure-Rust protox compiler) turns .proto text into a FileDescriptorSet, which is then registered through the stock protobuf DescriptorPool — making the resulting message classes indistinguishable from generated ones.

ruby integration of markdown-it-rust (with custom plugins)

An unofficial high-performance Rust-based gem for reading MaxMind DB files. Provides API compatibility with the official maxmind-db gem while leveraging Rust for superior performance. This library is not endorsed by MaxMind.

CSS parser/transformer for Mayu Live

Simple gem for quick MCP server creation