# mitchellh/libxev

libxev is a cross-platform, high-performance event loop that provides abstractions for non-blocking IO, timers, events, and more and works on Linux (io_uring or epoll), macOS (kqueue), and Wasm + WASI. Available as both a Zig and C API.

Repository: https://github.com/mitchellh/libxev
Canonical: https://ross.abutalabs.com/products/libxev
Language: Zig
License: MIT
License Family: permissive
Topics: async, c, epoll, io-uring, kqueue, wasi, webassembly, zig
Last push: 2026-07-17T05:22:40+00:00

## Health v2 (maintenance only)
Score: 73/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 93, release rhythm 35, longevity 95
- inputs: {"age_days": 1334, "days_push": 47, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3572, forks 187 (observed 2026-08-28T04:08:10.101984+00:00)

## What it is
libxev is a cross-platform, high-performance event loop library written in Zig that provides a unified proactor-style API for non-blocking IO, timers, signals, and events. It works on Linux (io_uring/epoll), macOS (kqueue), and WebAssembly (WASI and browser), and exposes both a Zig and C-compatible API.

## Use cases
- build a high-performance async event loop for a network server
- write non-blocking TCP/UDP socket code across Linux and macOS
- run an event loop in WebAssembly or WASI environments
- replace libuv with a zero-runtime-allocation event loop
- schedule timers and process management in a Zig or C application
- offload blocking file IO to a shared thread pool

## When to choose
- you need a libuv-style generalized event loop in Zig or C
- you want io_uring-style proactor semantics across multiple OS backends
- you target WebAssembly/WASI and need async IO without Emscripten
- predictable performance with zero runtime allocations matters, e.g. embedded or terminals

## When to avoid
- you need mature Windows support (still planned)
- you want a batteries-included async runtime with tasks and futures like Tokio
- your stack is far from C/Zig and higher-level language runtimes suffice

## Facets
- artifact type: library
- maturity: stable
- function: concurrency, networking, http-server, developer-tools
- domain: developer-tools, networking, cross-platform, performance, backend
- platform: wasm, cross-platform, cpp, rust, go
- tags: event-loop, io-uring, kqueue, epoll, proactor, async-io, zig, c-api, wasi, non-blocking-io, timers, linux, macos

## Member repositories
- mitchellh/libxev (main) score 73

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:10.101984+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:34:05.500629+00:00, confidence not recorded.
  - readme: https://github.com/mitchellh/libxev (fetched 2026-08-28T04:08:10.101984+00:00, sha 0561a5498b9d)
- Data as of 2026-08-30T08:39:29.467469+00:00.