Vapi helps developers build, test, and deploy voice agents at scale. We enable everything in between the raw models and production, including telephony, test suites, and real-time analytics.
Vapi's DTMF tool uses in-band tones, which may not work with all IVR systems—especially those expecting out-of-band DTMF. If your IVR supports speech input, try configuring your assistant to say the menu option (e.g., "Sales") instead of sending a DTMF digit. This is the recommended workaround when DTMF tones are not recognized and the call is getting ended. Example:
Vapi currently only supports in-band DTMF tones, which may not work with IVRs expecting out-of-band DTMF. The recommended workaround is to use speech input if the IVR supports it. If not, there is no documented way to send out-of-band DTMF via Vapi at this time.
To help us understand your scenario better: Does your IVR system provide any documentation or technical details about the DTMF method it expects (in-band vs. out-of-band)? This information will help us suggest the most appropriate next steps.
We are sending the DTMF tones from our side to the IVR navigation on call, but they are not receiving them. This could be an issue with the receiving party. Could you please check if it works for you outside VAPI phone numbers?
To verify the functionality of the DTMF tones, make a phone call using a different number (such as your own phone number) to the customer's phone number. When you press the digit, does it work? Can the customer's phone number receive the DTMF tones? If yes, try sending the DTMF tones using a Twilio phone number instead of the phone number provided by VAPI. If this doesn't resolve the issue, please share the call ID.