Imagine a user opens your app and decides to sign in with their phone number. Now, imagine that none of the usual challenges of signing in with a phone number stood in their way. No waiting for an SMS message, no waiting for them to be connected to a cell tower, they are just logged in within seconds.

Today, we’re excited to introduce the developer preview of Firebase Phone Number Verification (Firebase PNV), which lets you obtain the phone number of a SIM directly from the carrier over a secure API. No more users typing in numbers to get an SMS—just a single button tap does it all. Since it works seamlessly over both cellular and Wi-Fi, you can reach more end users, regardless of airplane mode, or cellular data connectivity. If the SIM is enabled and the device has an internet connection, you can get a verified phone number.

The problems with SMS one-time-passcodes

Verifying a user’s phone number is a critical part of onboarding, but it can be so much better. SMS one-time-passcodes (OTPs) can be challenging, forcing users to wait for a text and manually enter a code, with some users dropping off before they even get started. On top of that, artificially inflated traffic (AIT) can drive costs as an attacker generates SMS OTPs in an app that never result in verification. Sending SMS from your app increases the risk of phishing.

While there has been progress on phone number verification (PNV) since SMS OTPs reached peak popularity a few years ago, it isn’t a cure-all. IP-based phone number verification, often called “Header Enrichment”, requires the cellular data connection to be enabled, and sufficient cellular signal strength to obtain a phone number. In addition, they don’t fully protect the user from threats, including phishing. Many end users disable their cellular data to preserve precious bytes on their prepaid SIM card, or don’t have signal, so how do you verify their phone number in that state?

Verify phone numbers without SMS OTP

Firebase PNV can get the verified number of the device it’s running on in a second or two. Improve onboarding success rates and conversions by removing the need for users to type their phone number, plus it works great as part of a progressive onboarding flow. On top of that, you’re improving the security of your app by eliminating the risk of SMS traffic pumping (AIT), which means lower costs for a verification compared to SMS.

Since this feature requires that the user’s phone is on a compatible carrier, you’ll still need to fall back to an SMS OTP flow sometimes. The Firebase Phone Number Verification SDK lets you check for carrier compatibility in the background, so you can decide which UI to present to your users. That way, as we add new carriers, your app will automatically use them with no further changes required on your end, reducing reliance on SMS OTP over time.

Our first carrier partners: Deutsche Telekom and Telkomsel

We’re thrilled to launch the preview of Firebase PNV with our first carrier partners, Deutsche Telekom (Germany region) and Telkomsel (Indonesia region). Longer-term, our goal is to partner with more carriers and eventually provide the same coverage with Firebase PNV as you have today with SMS. We’ll be bringing more carriers and regions online in the coming months.

Get started with the developer preview

Ready to try the next generation of phone number verification? Head over to our documentation to learn more about integrating Firebase PNV into your app. We’re launching a developer preview and would love for you to try it out and help us shape the future of this product.

Fill out an interest form to be notified about onboarding announcements.

We’re looking forward to a more secure phone authentication future!