You can now verify phone numbers that sit behind an Interactive Voice Response (IVR) system using DTMF tones via the extension parameter. This update allows Telnyx to automatically navigate IVR menu prompts during a verification call, so even phone lines requiring an extension can receive and complete a verification code.
Telnyx’s verification APIs, Verify and Verified Numbers, now support an extension parameter that allows you to reach numbers behind IVR systems. The extension is a sequence of DTMF digits (0–9, A–D, *, #) with optional pause characters like w to introduce 0.5-second waits.
When a verification call is initiated with an extension, Telnyx first connects to the main number, waits for the IVR greeting, then automatically dials the provided DTMF sequence to navigate to the correct extension. Once the call reaches the intended destination, Telnyx plays the verification code so the user can complete the verification process.
This functionality is available via the API, enabling developers and teams to verify IVR-protected numbers programmatically or through the web interface.
Many organizations use main lines or call center numbers protected by multi-level IVRs, and this feature extends verification to those complex phone systems so no key contact point is overlooked. It closes a critical coverage gap, strengthening trust and demonstrating Telnyx’s commitment to supporting the real-world telephony setups businesses rely on.
Telnyx customers can start verifying IVR-protected numbers by following our quickstart guide or by using the extension parameter within the Verify API reference and Verified Numbers API reference.
