Sign in with Apple


Sign in with Apple is a single sign-on provider operated by Apple Inc., first unveiled on June 3, 2019 at Apple's 2019 Worldwide Developers Conference and introduced with iOS 13.
It is designed to allow users to create accounts for third-party services with a minimal amount of personal information, only requiring the user to provide a name and email address.
Users can opt for the email address associated with their Apple ID or choose the "Hide My Email" option to generate a disposable email address specific to the service; these addresses end in the privaterelay.appleid.com domain. Messages sent via a disposable email address are automatically forwarded to a verified email address of the user's choice, and this function can also be disabled if needed. The service is compatible with the OAuth 2.0 and OpenID Connect standards, and integrates with Face ID and Touch ID on iOS, iPadOS, and macOS.

Usage in software development

On September 12, 2019, Apple updated the App Store Review Guidelines to stipulate that developers whose apps use at least one third-party login service must implement Sign in with Apple, with exceptions for apps that function exclusively as a client for a specific service, that use a login service backed by a citizen identification system, or that are developed to work exclusively with a company's first-party login service.
Apple recommend in its human interface guidelines that the Sign in with Apple button be given due prominence over other third-party login services within user interfaces.
For use outside of iOS apps, Apple also offers a JavaScript library to implement Sign in with Apple on Android and the web.

Reception

Upon its unveiling, the OpenID Foundation issued a letter to Apple, stating that the service was not fully compliant with the OpenID Connect specifications. One of its exclusions was Proof Key for Code Exchange —whose absence exposed users to possible replay attacks and code injection vulnerabilities. In October 2019, it was announced that Apple had made the service compliant with OpenID Connect.