Swift

mise installs the Swift toolchains published on swift.org for macOS and Linux. Windows is not supported.

Quick start

Install Swift for the current project and check the selected toolchain:

mise use swift@6
mise exec -- swift --version

Use mise use -g swift@6 for a personal default. In an existing Swift package with a Package.swift, run mise exec -- swift build to build it.

Choosing a version

swift@6 selects the newest 6.x release, [email protected] selects that release, and swift@latest selects the newest release. List the available versions with mise ls-remote swift. See version requests for the full syntax.

Version files

mise can read .swift-version. Enable it for Swift:

mise settings add idiomatic_version_file_enable_tools swift

This changes your global config. Add --local to enable it in the project's mise.toml instead. See idiomatic version files.

Linux distributions

swift.org publishes Linux builds for specific releases of a few distribution families: Ubuntu, Debian, Fedora, Amazon Linux and Red Hat UBI. mise picks the build for your distribution's release, or the nearest older release in the same family. If the family only has builds for newer releases, mise warns and uses the oldest of them. If your family has no build at all, as on Arch Linux, mise warns and installs the UBI build. Set swift.platform, for example to ubuntu24.04, to choose a build explicitly. Every build links against glibc, so musl systems such as Alpine are not supported.

mise.lock records which distribution build an entry describes, so an entry written on Ubuntu does not apply on a Fedora machine, which installs the Fedora build instead.

How mise installs Swift

mise downloads the toolchain from download.swift.org. On Linux it verifies the archive's OpenPGP signature (swift.gpg_verify) and extracts it. On macOS it expands swift.org's installer package with pkgutil into mise's install directory; this toolchain is separate from the Swift that ships with Xcode. mise then links the swift* and sourcekit* executables into the install's bin directory and runs swift --version to check it. mise sets no Swift environment variables.

Troubleshooting

An installed plugin named swift takes precedence over the built-in installer. If mise behaves differently from this page, check mise plugins ls and see selecting another implementation.

Missing shared libraries

A build made for another distribution can ask for libraries under names your distribution does not use. Arch Linux, for example, ships only the wide-character ncurses (libncursesw.so.6), while the UBI build asks for libncurses.so.6. The install then fails at the swift --version check, and mise lists the libraries it could not find:

this swift build needs shared libraries missing from this host: libform.so.6, libncurses.so.6, libpanel.so.6 (point LD_LIBRARY_PATH at them with install_env)

When the names differ but the libraries are compatible, create a directory of aliases:

mkdir -p ~/.local/lib/curses-compat
ln -sf /usr/lib/libncursesw.so.6 ~/.local/lib/curses-compat/libncurses.so.6
ln -sf /usr/lib/libformw.so.6 ~/.local/lib/curses-compat/libform.so.6
ln -sf /usr/lib/libpanelw.so.6 ~/.local/lib/curses-compat/libpanel.so.6

Point the install at it with install_env, and point the installed toolchain at it with [env]:

mise.toml

[tools]
swift = { version = "6.4", install_env = { LD_LIBRARY_PATH = "{{env.HOME}}/.local/lib/curses-compat" } }

[env]
LD_LIBRARY_PATH = "{{env.HOME}}/.local/lib/curses-compat"

Alias a library only when the versions are compatible. If your distribution lacks the library entirely, install it.

Tool options

install_env

Sets environment variables for the swift --version check mise runs after installing, for pkgutil on macOS, and for postinstall commands. It does not affect the download. Its main use is the library workaround in Missing shared libraries. Other generic options are described in tool options.

Further reading

• A mise guide for Swift developers, from Tuist

Settings

Set these under [settings] in a config file, with mise settings set, or with a setting's environment variable where it has one. See which value wins when a setting is set in more than one place.

swift.gpg_verify

Verify the OpenPGP signature of Swift downloads on Linux.

• Type: boolean
• Default: true
• Environment variable: MISE_SWIFT_GPG_VERIFY

mise checks the signature itself, so gpg does not need to be installed. The global gpg_verify setting sets the default.

swift.platform

Linux distribution build of Swift to download, such as ubuntu24.04 or fedora41.

• Type: string
• Default: detected from your Linux distribution
• Environment variable: MISE_SWIFT_PLATFORM

By default, mise detects your distribution and picks the closest build that the Swift release publishes. Set this to force one build, or to install without fetching swift.org's release index. Ignored on macOS and Windows. See Linux distributions.