Sway is a language developed for the Fuel blockchain. It is heavily inspired by Rust and aims to bring modern language development and performance to the blockchain ecosystem.

For user documentation, including installing release builds, see the latest released Sway Book: https://fuellabs.github.io/sway/latest/.

The documentation URLs describe different source versions:

• latest redirects to the most recently published Sway release.
• vX.Y.Z is documentation built from that exact Sway release tag.
• master is built from the default branch and may describe unreleased behavior.

These labels are Sway documentation versions. They are not Fuelup channel names and do not identify the toolchain activated on a Fuel network. Check the compiler you are running with forc --version and consult the Fuelup channel documentation when selecting network-compatible tooling.

For Sway standard library documentation from the default branch, see https://fuellabs.github.io/sway/master/std/.

Also view the default-branch technical reference for the Sway programming language at https://fuellabs.github.io/sway/master/reference/.

The Stable Sway and Forc pages on docs.fuel.network are published by FuelLabs/docs-hub from an explicitly selected Sway release. That selection can differ from both the newest upstream release and the compiler in a named Fuelup network channel.

This section is for developing the Sway compiler and toolchain. For developing contracts and using Sway, see the above documentation section.

Sway is built in Rust. To begin, install the Rust toolchain following instructions at https://www.rust-lang.org/tools/install. Then configure your Rust toolchain to use Rust stable:

rustup default stable

If not already done, add the Cargo bin directory to your PATH by adding the following line to ~/.profile and restarting the shell session.

export PATH="${HOME}/.cargo/bin:${PATH}"

Clone the repository and build the Sway toolchain:

git clone git@github.com:FuelLabs/sway.git
cd sway
cargo build

Confirm the Sway toolchain built successfully:

cargo run --bin forc -- --help

For all other scripts and commands use https://github.com/casey/just:

> just --list
Available recipes:
    [automation]
    update-contract-ids
    update-fuel-dependencies

    [benchmark]
    benchmark
    benchmark-tests
    collect-gas-usage

    [build]
    build-highlightjs
    build-prism
    generate-sway-lib-std

    [ci]
    ci-check
    install-ci-check

    [test]
    test-forc-fmt-check-panic

We welcome contributions to Sway!

Please see the Contributing To Sway section of the Sway book for guidelines and instructions to help you get started.