Why do apps ask for your phone number?

More and more apps want a phone number before you can post, chat or play. It’s rarely about calling you. These are the usual reasons, and what you can do about each.

To stop spam and fake accounts

A new email address is quick to create, but a phone number takes more effort to get. Asking for one makes it harder to open hundreds of accounts, so many apps ask before you can message people or join groups. Discord, for example, asks when a server only lets in members with a verified phone, and Anthropic says Claude’s phone check is there to prevent spam and abuse.

To prove it’s you later

Apps send codes to the number when you sign in on a new device, reset your password, or when they notice something unusual. That’s why losing access to the number can lock you out.

For two-step sign-in

A text message is the simplest second step after a password, so many apps start there. Most also offer an authenticator app, which doesn’t depend on your number at all.

To know where you are

The country code tells an app where you are, and some services are only open in certain countries.

To find your friends, and for ads

Many apps match your number against other people’s contacts to suggest you as a friend, and some use it for ads. Look in the app’s privacy settings for contact syncing, “find me by phone number” and ad settings, and turn off what you don’t want. There’s more in how to keep your number private.

Your own number, or a separate one?

For apps you use every day, your own number is usually simplest, because it keeps recovery easy. For apps you only need to verify once, or would rather not link to your real number, a separate number keeps yours off their records. If you use a temporary one, follow these steps to keep the account afterwards.