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Signing a macOS app

Code signing is a security technology that you use to certify that an app was created by you.
On macOS, there are two layers of security technology for application distribution: code signing and notarization.
  • Code Signing is the act of certifying the identity of the app's author and ensuring it was not tampered with before distribution.
  • Notarization is an extra verification step where the app is sent to Apple servers for an automated malware scan.
From macOS 10.15 (Catalina) onwards, your application needs to be both code signed and notarized to run on a user's machine without disabling additional operating system security checks.
The exception is for Mac App Store (MAS) apps, where notarization is not required because the MAS submission process involves a similar automated check.

Prerequisites

Installing Xcode

Xcode is Apple's integrated development environment (IDE) for development on macOS, iOS, and other platforms.
Although Electron does not integrate tightly with the IDE itself, Xcode is a helpful tool for installing code signing certificates (see next section) and is required for notarization.

Obtaining signing certificates

Code signing certificates for macOS apps can only be obtained through Apple by purchasing a membership to the Apple Developer Program.
To sign Electron apps, you may require two separate certificates:
  • The Developer ID Installer certificate is for apps distributed to the Mac App Store.
  • The Developer ID Application certificate is for apps distributed outside the Mac App Store.
Once you have an Apple Developer Program membership, you first need to install them onto your machine. We recommend loading them through Xcode.
Verifying your certificate is installed
Once you have installed your certificate, you can check available code signing certificates in your terminal using the following shell command:
security find-identity -p codesigning -v

Configuring Forge

In Electron Forge, macOS apps are signed and notarized at the Package step by the electron-packager library. There is a separate option within your Forge packagerConfig for each one of these settings.

osxSign options

Under the hood, Electron Forge uses the @electron/osx-sign tool to sign your macOS application.
To enable code signing on macOS, ensure that packagerConfig.osxSign exists in your Forge configuration.
forge.config.js
module.exports = {
packagerConfig: {
osxSign: {} // object must exist even if empty
}
}
The osxSign config comes with defaults that work out of the box in most cases, so we recommend you start with an empty configuration object.
For a full list of configuration options, see the OsxSignOptions type in the Forge API docs. For more detailed information on how to configure these options, see the @electron/osx-sign documentation.

Customizing entitlements

A common use case for modifying the default osxSign configuration is to customize its entitlements. In macOS, entitlements are privileges that grant apps certain capabilities (e.g. access to the camera, microphone, or USB devices). These are stored within the code signature in an app's executable file.
By default, the @electron/osx-sign tool comes with a set of entitlements that should work on both MAS or direct distribution targets. See the complete set of default entitlement files on GitHub.
forge.config.js
module.exports = {
// ...
packagerConfig: {
// ...
osxSign: {
optionsForFile: (filePath) => {
// Here, we keep it simple and return a single entitlements.plist file.
// You can use this callback to map different sets of entitlements
// to specific files in your packaged app.
return {
entitlements: 'path/to/entitlements.plist'
}
}
}
}
// ...
}
For further reading on entitlements, see the following pages in Apple developer documentation:

osxNotarize options

Under the hood, Electron Forge uses the @electron/notarize tool to notarize your macOS application.
The osxNotarize configuration object can be set up to either use the legacy or notarytool strategies. If you are using Xcode 13 or higher, we strongly recommend using notarytool. The legacy tooling will be removed when Apple sunsets altool (projected for Fall 2023).
The notarytool command has three authentication options, which are detailed below. Note that you will want to use a forge.config.js configuration so that you can load environment variables into your Forge config.
Keep your authentication details private
You should never store authentication info in plaintext in your configuration. In the examples below, credentials are stored as environment variables and accessed via the Node.js process.env object.

Option 1: Using an app-specific password

You can generate an app-specific password from Apple to provide your credentials to notarytool. This password will need to be regenerated if you change your Apple ID password.
There are two mandatory fields for osxNotarize if you are using this strategy:
Field
Type
Description
appleId
string
Apple ID associated with your Apple Developer account
appleIdPassword
string
App-specific password
teamId
string
The Apple Team ID you want to notarize under. You can find Team IDs for team you belong to by going to https://developer.apple.com/account/#/membership
forge.config.js
module.exports = {
//...
packagerConfig: {
// ...
osxNotarize: {
tool: 'notarytool',
appleId: process.env.APPLE_ID,
appleIdPassword: process.env.APPLE_PASSWORD,
teamId: process.env.APPLE_TEAM_ID,
}
}
//...
}
Despite the name, appleIdPassword is not the password for your Apple ID account.

Option 2: Using an App Store Connect API key

You can generate an App Store Connect API key to authenticate notarytool by going to the App Store Connect access page and using the "Keys" tab. This API key will look something like AuthKey_ABCD123456.p8 and can only be downloaded once.
There are three mandatory fields for osxNotarize if you are using this strategy:
Field
Type
Description
appleApiKey
string
Filesystem path string to your API key file.
appleApiKeyId
string
10-character alphanumeric ID string. In the previous AuthKey_ABCD123456.p8 example, this would be ABCD123456.
appleApiIssuer
string
UUID that identifies the API key issuer. You will find this ID in the "Keys" tab where you generated your API key.
forge.config.js
module.exports = {
//...
packagerConfig: {
// ...
osxNotarize: {
tool: 'notarytool',
appleApiKey: process.env.APPLE_API_KEY
appleApiKeyId: process.env.APPLE_API_KEY_ID
appleApiIssuer: process.env.APPLE_API_ISSUER
}
}
//...
}

Option 3: Using a keychain

Instead of providing environment variables to the Forge config passed to notarytool, you can choose to use a macOS keychain containing either set of credentials (either Option 1 or Option 2 above).
You can do this directly in your terminal via the notarytool store-credentials command. For usage information, you can refer to the man page for notarytool:
man notarytool
There are two mandatory fields for osxNotarize if you are using this strategy:
Field
Type
Description
keychain
string
Name of (or path to) the keychain containing the profile with your credentials.
keychainProfile
string
Name of the keychain profile containing your notarization credentials.
forge.config.js
module.exports = {
//...
packagerConfig: {
// ...
osxNotarize: {
tool: 'notarytool',
keychain: 'my-keychain'
keychainProfile: 'my-keychain-profile'
}
}
//...
}

Example configuration

Below is a minimal Forge configuration for osxSign and osxNotarize.
forge.config.js
module.exports = {
packagerConfig: {
osxSign: {},
osxNotarize: {
tool: 'notarytool',
appleId: process.env.APPLE_ID,
appleIdPassword: process.env.APPLE_PASSWORD,
teamId: process.env.APPLE_TEAM_ID
},
},
};