--- title: "Async I/O in Zig 0.16, today" url: https://daily.dev/posts/async-i-o-in-zig-0-16-today-tn11ikcsj source_url: https://lalinsky.com/2026/05/11/async-io-in-zig-016-today.html type: article source: "Lobsters" published: 2026-05-17T08:25:04.188Z updated: 2026-05-17T08:25:30.498Z tags: ["zig"] reading_time: 3 upvotes: 13 comments: 1 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Async I/O in Zig 0.16, today **[Lobsters](https://daily.dev/sources/lobsters)** · 3 min read · 13 upvotes · 1 comments ## Summary Zig 0.16 introduced std.Io, a cross-platform I/O and concurrency interface, but the only working implementation (std.Io.Threaded) spawns OS threads, making it unsuitable for high-concurrency workloads. The author presents zio 0.11, a drop-in std.Io implementation using stackful coroutines and native async OS APIs (io_uring/epoll on Linux, kqueue on BSD/macOS, IOCP on Windows). A benchmark shows 10,000 concurrent sleeping tasks completing in ~10 seconds with zio versus ~20 seconds with the threaded implementation, and zio scales to 50,000+ tasks without hitting OS thread limits. The API is nearly identical to std.Io.Threaded — just initialize a zio runtime and pass its io() handle anywhere std.Io is expected, including std.http.Server. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Zig's New Async I/O \(Text Version\)](https://daily.dev/posts/zig-s-new-async-i-o-text-version--ikopqzdkc) · Lobsters · 7 upvotes · 0 comments - [Zig's new plan for asynchronous programs](https://daily.dev/posts/zig-s-new-plan-for-asynchronous-programs-ac61co56j) · Lobsters · 5 upvotes · 3 comments --- Tags: [#zig](https://daily.dev/tags/zig) [View this post on daily.dev](https://daily.dev/posts/async-i-o-in-zig-0-16-today-tn11ikcsj)