Just Once enables you to generate one-time passwords (OTPs) - like you would know them from software or hardware authenticators (e.g. Google Authenticator or Yubi Key respectively) - to increase the security of your users through multi-factor authentication. The plugin enables you to create time-based OTPs (TOTP), as described in RFC 6238, as well as counter-based OTPs (HOTP), as described in RFC 4226. You can import keys from other places, or create new keys (randomly or by seed) for the generation of OTPs.

You can configure the OTP generation to have a specific digit length (between 3 and 10, default is 6), customize the interval for which it is valid (default is 30 seconds) in case of TOTPs or define the counter value in case of HOTP through a set of ready-to-use blueprints. Those also double as reference implementation, since you are encouraged to integrate the OTP generation flow so it fits your application most appropriately. The demo project will showcase the setup and usage of the blueprints coming with the plugin.

Just Once will also enable you to conveniently generate QR codes, as well as the underlying otpauth URI for linking other devices / authenticators.