*[TokioConf 2026 program and tickets are now available!](https://tokioconf.com)*---# TokioA runtime for writing reliable, asynchronous, and slim applications withthe Rust programming language. It is:* **Fast**: Tokio's zero-cost abstractions give you bare-metal  performance.* **Reliable**: Tokio leverages Rust's ownership, type system, and  concurrency model to reduce bugs and ensure thread safety.* **Scalable**: Tokio has a minimal footprint, and handles backpressure  and cancellation naturally.[![Crates.io][crates-badge]][crates-url][![MIT licensed][mit-badge]][mit-url][![Build Status][actions-badge]][actions-url][![Discord chat][discord-badge]][discord-url][crates-badge]: https://img.shields.io/crates/v/tokio.svg[crates-url]: https://crates.io/crates/tokio[mit-badge]: https://img.shields.io/badge/license-MIT-blue.svg[mit-url]: https://github.com/tokio-rs/tokio/blob/master/LICENSE[actions-badge]: https://github.com/tokio-rs/tokio/workflows/CI/badge.svg[actions-url]: https://github.com/tokio-rs/tokio/actions?query=workflow%3ACI+branch%3Amaster[discord-badge]: https://img.shields.io/discord/500028886025895936.svg?logo=discord&style=flat-square[discord-url]: https://discord.gg/tokio[Website](https://tokio.rs) |[Guides](https://tokio.rs/tokio/tutorial) |[API Docs](https://docs.rs/tokio/latest/tokio) |[Chat](https://discord.gg/tokio)## OverviewTokio is an event-driven, non-blocking I/O platform for writingasynchronous applications with the Rust programming language. At a highlevel, it provides a few major components:* A multithreaded, work-stealing based task [scheduler].* A reactor backed by the operating system's event queue (epoll, kqueue,  IOCP, etc.).* Asynchronous [TCP and UDP][net] sockets.These components provide the runtime components necessary for buildingan asynchronous application.[net]: https://docs.rs/tokio/latest/tokio/net/index.html[scheduler]: https://docs.rs/tokio/latest/tokio/runtime/index.html## ExampleA basic TCP echo server with Tokio.Make sure you enable the full features of the tokio crate on Cargo.toml:```toml[dependencies]tokio = { version = "1.52.3", features = ["full"] }```Then, on your main.rs:```rust,no_runuse tokio::net::TcpListener;use tokio::io::{AsyncReadExt, AsyncWriteExt};#[tokio::main]async fn main() -> Result<(), Box<dyn std::error::Error>> {    let listener = TcpListener::bind("127.0.0.1:8080").await?;    loop {        let (mut socket, _) = listener.accept().await?;        tokio::spawn(async move {            let mut buf = [0; 1024];            // In a loop, read data from the socket and write the data back.            loop {                let n = match socket.read(&mut buf).await {                    // socket closed                    Ok(0) => return,                    Ok(n) => n,                    Err(e) => {                        eprintln!("failed to read from socket; err = {:?}", e);                        return;                    }                };                // Write the data back                if let Err(e) = socket.write_all(&buf[0..n]).await {                    eprintln!("failed to write to socket; err = {:?}", e);                    return;                }            }        });    }}```More examples can be found [here][examples]. For a larger "real world" example, see the[mini-redis] repository.[examples]: https://github.com/tokio-rs/tokio/tree/master/examples[mini-redis]: https://github.com/tokio-rs/mini-redis/To see a list of the available feature flags that can be enabled, check our[docs][feature-flag-docs].## Getting HelpFirst, see if the answer to your question can be found in the [Guides] or the[API documentation]. If the answer is not there, there is an active community inthe [Tokio Discord server][chat]. We would be happy to try to answer yourquestion. You can also ask your question on [the discussions page][discussions].[Guides]: https://tokio.rs/tokio/tutorial[API documentation]: https://docs.rs/tokio/latest/tokio[chat]: https://discord.gg/tokio[discussions]: https://github.com/tokio-rs/tokio/discussions[feature-flag-docs]: https://docs.rs/tokio/#feature-flags## Contributing:balloon: Thanks for your help improving the project! We are so happy to haveyou! We have a [contributing guide][guide] to help you get involved in the Tokioproject.[guide]: https://github.com/tokio-rs/tokio/blob/master/docs/contributing/README.md## Related ProjectsIn addition to the crates in this repository, the Tokio project also maintainsseveral other libraries, including:* [`axum`]: A web application framework that focuses on ergonomics and modularity.* [`hyper`]: A fast and correct HTTP/1.1 and HTTP/2 implementation for Rust.* [`tonic`]: A gRPC over HTTP/2 implementation focused on high performance, interoperability, and flexibility.* [`warp`]: A super-easy, composable, web server framework for warp speeds.* [`tower`]: A library of modular and reusable components for building robust networking clients and servers.* [`tracing`] (formerly `tokio-trace`): A framework for application-level tracing and async-aware diagnostics.* [`mio`]: A low-level, cross-platform abstraction over OS I/O APIs that powers `tokio`.* [`bytes`]: Utilities for working with bytes, including efficient byte buffers.* [`loom`]: A testing tool for concurrent Rust code.[`axum`]: https://github.com/tokio-rs/axum[`warp`]: https://github.com/seanmonstar/warp[`hyper`]: https://github.com/hyperium/hyper[`tonic`]: https://github.com/hyperium/tonic[`tower`]: https://github.com/tower-rs/tower[`loom`]: https://github.com/tokio-rs/loom[`tracing`]: https://github.com/tokio-rs/tracing[`mio`]: https://github.com/tokio-rs/mio[`bytes`]: https://github.com/tokio-rs/bytes## ChangelogThe Tokio repository contains multiple crates. Each crate has its own changelog. * `tokio` - [view changelog](https://github.com/tokio-rs/tokio/blob/master/tokio/CHANGELOG.md) * `tokio-util` - [view changelog](https://github.com/tokio-rs/tokio/blob/master/tokio-util/CHANGELOG.md) * `tokio-stream` - [view changelog](https://github.com/tokio-rs/tokio/blob/master/tokio-stream/CHANGELOG.md) * `tokio-macros` - [view changelog](https://github.com/tokio-rs/tokio/blob/master/tokio-macros/CHANGELOG.md) * `tokio-test` - [view changelog](https://github.com/tokio-rs/tokio/blob/master/tokio-test/CHANGELOG.md)## Supported Rust Versions<!--When updating this, also update:- .github/workflows/ci.yml- CONTRIBUTING.md- README.md- tokio/README.md- tokio/Cargo.toml- tokio-util/Cargo.toml- tokio-test/Cargo.toml- tokio-stream/Cargo.toml-->Tokio will keep a rolling MSRV (minimum supported rust version) policy of **atleast** 6 months. When increasing the MSRV, the new Rust version must have beenreleased at least six months ago. The current MSRV is 1.71.Note that the MSRV is not increased automatically, and only as part of a minorrelease. The MSRV history for past minor releases can be found below: * 1.48 to now  - Rust 1.71 * 1.39 to 1.47 - Rust 1.70 * 1.30 to 1.38 - Rust 1.63 * 1.27 to 1.29 - Rust 1.56 * 1.17 to 1.26 - Rust 1.49 * 1.15 to 1.16 - Rust 1.46 * 1.0 to 1.14 - Rust 1.45Note that although we try to avoid the situation where a dependency transitivelyincreases the MSRV of Tokio, we do not guarantee that this does not happen.However, every minor release will have some set of versions of dependencies thatworks with the MSRV of that minor release.## Release scheduleTokio doesn't follow a fixed release schedule, but we typically make one minorrelease each month. We make patch releases for bugfixes as necessary.## Bug patching policyFor the purposes of making patch releases with bugfixes, we have designatedcertain minor releases as LTS (long term support) releases. Whenever a bugwarrants a patch release with a fix for the bug, it will be backported andreleased as a new patch release for each LTS minor version. Our current LTSreleases are: * `1.47.x` - LTS release until September 2026. (MSRV 1.70) * `1.51.x` - LTS release until March 2027. (MSRV 1.71)Each LTS release will continue to receive backported fixes for at least a year.If you wish to use a fixed minor release in your project, we recommend that youuse an LTS release.To use a fixed minor version, you can specify the version with a tilde. Forexample, to specify that you wish to use the newest `1.47.x` patch release, youcan use the following dependency specification:```texttokio = { version = "~1.47", features = [...] }```### Previous LTS releases * `1.8.x` - LTS release until February 2022. * `1.14.x` - LTS release until June 2022. * `1.18.x` - LTS release until June 2023. * `1.20.x` - LTS release until September 2023. * `1.25.x` - LTS release until March 2024. * `1.32.x` - LTS release until September 2024. * `1.36.x` - LTS release until March 2025. * `1.38.x` - LTS release until July 2025. * `1.43.x` - LTS release until March 2026.## LicenseThis project is licensed under the [MIT license].[MIT license]: https://github.com/tokio-rs/tokio/blob/master/LICENSE### ContributionUnless you explicitly state otherwise, any contribution intentionally submittedfor inclusion in Tokio by you shall be licensed as MIT, without any additionalterms or conditions.