# tokio-rs/mio

Metal I/O library for Rust.

Repository: https://github.com/tokio-rs/mio
Canonical: https://ross.abutalabs.com/products/mio
Language: Rust
License: MIT
License Family: permissive
Topics: rust, non-blocking, asynchronous, networking
Last push: 2026-08-17T16:59:26+00:00

## Health v2 (maintenance only)
Score: 67/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 98, release rhythm 8, longevity 100
- inputs: {"age_days": 4396, "days_push": 16, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 7088, forks 861 (observed 2026-08-28T04:09:55.839649+00:00)

## What it is
Mio is a fast, low-level I/O library for Rust providing non-blocking APIs and OS event notification (epoll, kqueue, IOCP) for building high-performance networked applications. It is the foundation layer underneath Tokio and other async runtimes.

## Use cases
- build a high-performance non-blocking TCP server in Rust
- write a custom event loop over epoll/kqueue/IOCP
- implement an async runtime or executor from scratch
- handle thousands of concurrent sockets with minimal overhead
- wrap OS I/O readiness events in a portable API

## When to choose
- you need maximum I/O performance with minimal abstraction overhead
- you are building your own async runtime or low-level networking library
- you want direct, portable access to OS readiness events

## When to avoid
- you want an easy high-level async API - use Tokio instead
- you need blocking I/O or simple synchronous networking
- you want built-in tasks, timers, or channels - Mio only provides event notification

## Facets
- artifact type: library
- maturity: stable
- function: networking, concurrency, developer-tools
- domain: networking, developer-tools, performance
- platform: rust, windows, cross-platform
- tags: non-blocking-io, event-loop, epoll, kqueue, iocp, async-runtime-foundation, linux, macos

## Member repositories
- tokio-rs/mio (main) score 67

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:55.839649+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 2026-08-29T17:40:10.775989+00:00, confidence not recorded.
  - readme: https://github.com/tokio-rs/mio (fetched 2026-08-28T04:09:55.839649+00:00, sha a72320026379)
  - registry_crates: https://crates.io/api/v1/crates/mio (fetched 2026-08-29T08:35:51.020263+00:00, sha 44a1b15468aa)
- Data as of 2026-08-30T08:39:29.467469+00:00.