Verification codes are a security protection method used to avoid internet bots from abusing or even spamming various online services.

Note that this form of verification code is not limited to Authenticator, which is just one of many similar options. Any service can provide verification services to website creators and users. These services are typically used for traditional banking accounts and two-factor authentication (2FA) crypto assets, which require a high level of security.

The verification code can also be a 4-digit PIN code sent to your cell phone via SMS. But it can also be done by calling and taking the last 4 digits of the number calling your number. Sending the code using this method serves to verify your cellphone number. This code can only be used once.

Besides captcha images, another form of verification is the Google Verification code, which is a short numeric code sent directly to the user, usually by phone or email that is used to verify their identity.