firebase_pnv is an unofficial Flutter plugin for Google's Firebase Phone Number Verification (PNV) SDK. Instead of texting the user a one-time SMS code they have to manually type back, Firebase PNV verifies their number directly with their mobile carrier in the background using the Android Credential Manager.
The user just taps "Allow" on a native consent sheet. No text messages are sent, and no codes are typed.
Because this flow skips SMS entirely, it completely protects you against SMS pumping and toll fraud. It is currently Android-only, but the package includes a safe stub for iOS so your shared codebase does not break.
How it works
- Check support - You run a quick check to see if the device and SIM support carrier verification.
- Trigger verification - If supported, call the verification method to show the native Google consent sheet.
- Get token - If the user accepts, you get a verified phone number and an auth token.
- Exchange token - Pass the token to your backend, verify it against Google's JWKS endpoint, and mint a custom Firebase token to log the user in.
Why use it
- Zero SMS costs - Since no text messages are sent, there is zero risk of SMS pumping fraud.
- Better conversion - The verification finishes in seconds without making the user wait for an SMS code and type it in.
- Clean fallback - If PNV is not supported or fails, you can fall back to standard Firebase Auth SMS verification.