Authentication apps are apps that verify users. In the context of two-factor authentication, the phrase "authentication apps" refers to apps that generate unique time-limited verification codes.
For information on how to set up authentication apps, please check this article.
Examples of authentication apps
Commonly used authentication apps include Google Authenticator and Microsoft Authenticator. If you are new to authentication apps, we recommend using one of these two.
These authentication apps contain a backup feature. If the backup feature is enabled, your data may be restorable to another device even if your original device is lost or broken. To learn more, please check the Help pages on the websites of each authentication app.
Google Authenticator
Download iOS version here
Download Android version here
Check here for Official Help page
Microsoft Authenticator
Download iOS version here
Download Android version here
Check here for Official Help page
Why is it possible to use authentication apps from third-party companies?
Most authentication apps comply with a standard called Time-Based One-Time Password (TOTP). This standard stipulates a mechanism for generating a time-based, one-time-use verification code based on a Secret Key shared between the authentication app and the server.
pixiv incorporates an authentication feature that complies with TOTP, so any TOTP-compliant authentication app may be used with pixiv. pixiv Inc. does not provide its own authentication app, so to enable two-factor authentication, you must use an authentication app provided by a third-party company.
Warning when changing devices
If you change your device, you must transfer your authentication app data to your new device.
If you use an authentication app with a backup feature, you may be able to use the backup feature to restore your data on your new device, thereby transferring the data. However, in some cases, even with a backup feature, if the OS on the two devices is different, the data may not be able to be restored, so please check the authentication app Help pages in advance, before you change your device.
If you cannot transfer your data due to the features of your authentication app, you will need to reset your authentication app from the pixiv two-factor authentication settings page. Please do not delete the data on your old device until all the data has been successfully transferred to your new device.