Introducing Silent Authentication Advanced in the Verify API

Today, we're thrilled to announce the Alpha launch of Silent Authentication Advanced within the Vonage Verify API. This new channel represents a major evolution in device-based identity verification. No longer limited to cellular networks, it delivers world-class security and a smooth, seamless experience over Wi-Fi and VPN.

We invite developers and security architects in the USA to be the first to test and integrate this next-generation authentication flow.

What is Silent Authentication Advanced?

Silent Authentication is a passwordless authentication method in Vonage Verify that confirms a user’s identity through their mobile network with no OTPs to send, copy, or intercept. Compared to SMS OTPs, Silent Authentication is up to 50% faster, far more resilient to phishing and social engineering, and designed to enhance customer experience and improve conversion rates.

Silent Authentication Advanced is a new channel in the Verify API workflow that supports authentication over Wi-Fi and VPN connections. Here’s an example of how to define it:

{
   "brand": "ACME",
   "workflow": [
      {
         "channel": "silent authentication advanced",
         "to": "+990XXXXXX",
         "temp_token": "SplxlOBeZQQYbYS6WxSbIA"
      },
   ]
}

If the Silent Authentication Advanced check fails (e.g., due to an unsupported device type), Verify automatically falls back to your secondary channels (SMS or voice). Vonage now offers two versions of Silent Authentication: Standard (formerly simply “Silent Authentication”) and Advanced. Both eliminate OTP friction but rely on different network signals, making each better suited to specific use cases.

Silent Authentication Standard (IP-based)

Silent Authentication Standard follows an IP-based verification. It verifies phone-number possession by correlating the user’s public IP address with the mobile data session managed by the operator. If the IP and MSISDN match, the operator confirms the user is in possession of their number, all in the background, without disrupting the customer journey.

Silent Authentication Advanced (Token-based)

Silent Authentication Advanced is built on a new network-verification technology: the GSMA TS.43 protocol. Instead of relying on IP correlation, it performs a direct SIM-to-network authentication inside the operator’s core. This cryptographic check verifies that the actual SIM card linked to the phone number is present and active, regardless of whether the user is using mobile data, Wi-Fi, or a VPN.

Choosing the Right Version

The Silent Authentication Standard provides much stronger security than OTPs over SMS and other channels and can automatically fall back to other verification methods when Silent Authentication cannot be completed. However, for enterprise scenarios that require consistent performance across Wi-Fi and VPN, or for industries that demand the highest possible level of security, Silent Authentication Advanced can be the better choice.

Silent Authentication Standard is a mature, widely available technology, and Vonage already provides it across 15 countries. Silent Authentication Advanced is a newer technology with global adoption still ramping up, and only a limited number of mobile operators support it. Both approaches are available as part of the single Vonage Verify API.

Join the Alpha Program: Available Now in the USA

We are rolling out Silent Authentication Advanced in a phased approach, starting with developers focused on the US market.

Phase 1: Demo & Docs Ready (Live): We are live with our Alpha product demonstration with supporting developer documentation. Come read about our product plans and where we plan to launch initial coverage. Don’t forget to register your interest for the Alpha product program!

Phase 2: Virtual Operator Testing (Coming Soon): We have integrated a Virtual Operator (VO) layer into the Verify API. This environment allows you to begin integration immediately with deterministic test numbers (+990 routing), enabling you to fully test your backend logic, webhook processing, and overall flow handling before connecting to live carrier infrastructure.

Phase 3: Live Carrier Supply. Following successful VO testing, we are actively integrating with live Communication Service Providers (CSPs) in the USA. As this supply becomes available, Alpha participants will be the first to route live traffic through Silent Authentication Advanced.

Get exclusive access: This initial Alpha program is your opportunity to integrate Silent Authentication Advanced ahead of the market and provide vital feedback, directly influencing the final API and documentation before general availability.

Ready to secure your mobile users and eliminate OTP friction?

👉Register for the Silent Authentication Advanced Alpha Program Today(Space is limited for this initial Alpha launch, and the trial period is currently offered at no charge.)

Conclusion

Silent Authentication Advanced represents a major step forward in enterprise-grade mobile identity. By extending secure, SIM-based verification to Wi-Fi and VPN environments, it closes critical coverage gaps that have long limited high-assurance authentication flows. With this new channel, enterprises can finally deploy a unified authentication strategy that delivers stronger security, higher reliability, and a fully frictionless user experience at scale.