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Number Verification API

Secure, seamless, and passwordless authentication for mobile apps — all through the network.

Forget the extra steps with emails, calls, or one-time passcodes (OTPs) for customer authentication. Vonage Number Verification API uses the mobile device’s number itself as an identity credential — and confirms that the number matches the SIM data for validation — through a direct carrier connection. And it’s all without any input from the end user. This behind-the-scenes validation offers a safer, faster, and better customer experience.

See developer documentation
Illustration of Number Verification



Enhanced security

By eliminating the need for OTPs, the risk of interception or phishing attacks is greatly reduced: the direct carrier connection ensures that the number validation is secure and tamper-proof.

Improved user experience

Because the authentication process happens automatically in the background - with no action needed from the user to wait for and manually enter in a password- it’s frictionless and faster.

Increased operational savings

Optimized for higher conversion rates, reduced customer abandonment and lower churn rates, ultimately resulting in operational savings.
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Greater reliability

The direct carrier connection ensures a higher success rate for authentication. Why? It doesn’t rely on the delivery of OTPs, which can sometimes fail due to network issues or spam filters.




How Number Verification API works in the real world

From online banking to rideshares, there’s a myriad of ways that Number Verification API can be used to create safer, better experiences.  

  • Self-service banking: Allow customers to open and activate accounts, transfer money, and check balances securely.

  • Verification for account changes: Simplify the verification of customer updates, such as password changes, password resets, or contact information.

  • Payments and transactions: Authorize sales and collect payments securely and enable quick guest checkouts.

  • Secure file access: Ensure that only authorized personnel can access sensitive documents and data.

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Get access to Number Verification API through the Vonage Network Registry.

The Vonage Network Registry reduces network complexities for developers, businesses, and communication service providers (CSPs) and:

  • Offers a single process and centralized location for developers to register for access to Network APIs and CSP networks.

  • Makes it easy for CSPs to securely scale and standardize network access for developers and customers.

  • Provides enterprises and developers with convenient access to network capabilities, using Vonage Network APIs, to build better and more secure apps.

Vonage APIs for Security

Number Verification, SIM Swap: Which API is right for you? Vonage solutions help make your mobile apps more secure, with less disruption to your customers.

Type of API

Best for…

Avoid if…

Number Verification API

Developers who have their own failover methods and want a stand-alone API to customize the user journey

You’re looking for failover methods like SMS or email if there is not coverage

Combining with a 2FA workflow to ensure that a phone number has not recently changed SIM cards.

Your business does not require an extra layer of security checks - this could be unnecessary



Image illustrating Sim Swap

What goes well with Number Verification? Our SIM Swap API (Beta)

The SIM Swap API allows developers to determine if the SIM card linked to the phone number has recently changed. This gives developers the assurance that the phone number can be used for multiple use cases — like two-factor authentication or as a secure communications channel.

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For Communications Service Providers

Monetize your network investment - partner with us today

If you’re a CSP, you’ve already invested billions in 5G network upgrades. Our Network APIs can help you take that investment to the next level — and transform your network into a programmable service platform.

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