Create fictional phone numbers and verification codes
In the Firebase console, open the Authentication section.
In the Sign in method tab, enable the Phone provider if you haven't already.
Open the Phone numbers for testing accordion menu.
Provide the phone number you want to test, for example: +1 650-555-3434.
Provide the 6-digit verification code for that specific number, for example: 654321.
Add the number. If there's a need, you can delete the phone number and its code by hovering over the corresponding row and clicking the trash icon.
Manual testing
You can directly start using a fictional phone number in your application. This allows you to perform manual testing during development stages without running into quota issues or throttling. You can also test directly from an iOS simulator or Android emulator without Google Play Services installed.
When you provide the fictional phone number and send the verification code, no actual SMS is sent. Instead, you need to provide the previously configured verification code to complete the sign in.
On sign-in completion, a Firebase user is created with that phone number. The user has the same behavior and properties as a real phone number user, and can access Realtime Database/Cloud Firestore and other services the same way. The ID token minted during this process has the same signature as a real phone number user.