.app bundle

Host Platform Support (Platform support)

macOS

Windows

Linux

x86‑64

arm64

x86

x86‑64

arm64

x86

x86‑64

arm

arm64

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A macOS .app bundle is a collection of directory with a specific layout, and with some key metadata. If this structure and metadata exists, macOS treats the folder as an executable file, giving it an icon.

.app bundles can be copied around as if they are a single file. They can also be compressed to reduce their size for transport.

By default, apps will be both signed and notarized when they are packaged.

Packaging format

Briefcase supports three packaging formats for a macOS app:

  1. A DMG that contains the .app bundle (using briefcase package macOS -p dmg).

  2. A zipped .app folder (using briefcase package macOS -p zip).

  3. A .pkg installer (using briefcase package macOS -p pkg).

.pkg is the required format for console apps. .dmg is the default format for GUI apps.

Icon format

macOS .app bundles use .icns format icons.

macOS .app bundles do not support splash screens or installer images.

Additional options

The following options can be provided at the command line when packaging macOS apps.

--installer-identity <identity>

This option is only used when creating a .pkg installer.

The code signing identity to use when signing the installer package. This is a different signing identity to the one used to sign the app, but it must be from the same team as the app signing identity.

--no-sign-installer

This option is only used when creating a .pkg installer.

Do not sign the installer. This option can be useful during development and testing. However, care should be taken using this option for release artefacts, as it may not be possible to distribute an unsigned installer to others.

--no-notarize

Do not submit the application for notarization. By default, apps will be submitted for notarization unless they have been signed with an ad-hoc signing identity.

Application configuration

The following options can be added to the tool.briefcase.app.<appname>.macOS.app section of your pyproject.toml file.

entitlement

A property whose sub-attributes define keys that will be added to the app’s Entitlements.plist file. Each entry will be converted into a key in the entitlements file. For example, specifying:

entitlement."com.apple.vm.networking" = true

will result in an Entitlements.plist declaration of:

<key>com.apple.vm.networking</key><true/>

Any Boolean, string, list, or dictionary value can be used as an entitlement value.

All macOS apps are automatically granted the following entitlements by default:

  • com.apple.security.cs.allow-unsigned-executable-memory

  • com.apple.security.cs.disable-library-validation

You can disable these default entitlements by defining them manually. For example, to enable library validation, you could add the following to your pyproject.toml:

entitlement."com.apple.security.cs.disable-library-validation" = false

info

A property whose sub-attributes define keys that will be added to the app’s Info.plist file. Each entry will be converted into a key in the entitlements file. For example, specifying:

info."NSAppleScriptEnabled" = true

will result in an Info.plist declaration of:

<key>NSAppleScriptEnabled</key><true/>

Any Boolean or string value can be used for an Info.plist value.

universal_build

A Boolean, indicating whether Briefcase should build a universal app (i.e, an app that can target both x86_64 and ARM64). Defaults to true; if false, the binary will only be executable on the host platform on which it was built - i.e., if you build on an x86_64 machine, you will produce an x86_65 binary; if you build on an ARM64 machine, you will produce an ARM64 binary.

Permissions

Briefcase cross platform permissions map to a combination of info and entitlement keys:

  • microphone: an entitlement of com.apple.security.device.audio-input

  • camera: an entitlement of com.apple.security.device.camera

  • coarse_location: an info entry for NSLocationUsageDescription (ignored if background_location or fine_location is defined); plus an entitlement of com.apple.security.personal-information.location

  • fine_location: an info entry for NSLocationUsageDescription``(ignored if ``background_location is defined); plus an entitlement of com.apple.security.personal-information.location

  • background_location: an info entry for NSLocationUsageDescription; plus an entitlement of com.apple.security.personal-information.location

  • photo_library: an entitlement of com.apple.security.personal-information.photos-library

Platform quirks

Packaging with --adhoc-sign

Using the --adhoc-sign option on macOS produces an app that will be able to run on your own machine, but won’t run on any other computer. In order to distribute your app to other users, you will need to sign the app with a full signing identity.