Why add voice OTP to your login or checkout?
Recover failed SMS OTPs
When an SMS OTP is delayed by network congestion or the user's phone, a voice call gets the code through, so fewer sign-ups and payments are abandoned.
Reach every phone
Voice calls work on feature phones and landlines and for users who find it hard to read SMS, which matters across Tier-2 and Tier-3 India.
Confirm with a key press
Ask "Press 1 to confirm this payment" or "Press 1 to confirm your order" and capture the DTMF response in real time.
Runs 24x7, including DND
Voice OTP is a service communication triggered by the user, so it is not limited by promotional time windows or DND/NCPR blocking.
How SMS-to-voice OTP fallback works
- The user requests an OTP; your app sends it by SMS OTP first.
- If the code is not verified within your timeout (for example 30 seconds), your app calls our voice OTP API, or shows a "Call me instead" button.
- Our platform calls the user from your DLT-registered voice header and reads the code aloud, digit by digit and repeated.
- Optionally the user presses a key to confirm, and the result is returned to you in the delivery report.
Voice OTP pricing
Prepaid packs on the dedicated service route, billed per connected call on a 30-second pulse with 1-year validity. Rates exclude 18% GST.
| Pack | Rate per connected call | Pack amount (excl. GST) |
|---|
| 10,000 calls | ₹0.42 | ₹4,200 |
| 25,000 calls | ₹0.37 | ₹9,250 |
| 50,000 calls | ₹0.32 | ₹16,000 |
| 1,00,000 calls | ₹0.30 | ₹30,000 |
Need more than 5,00,000 calls? Ask for a volume quote. Full details and Buy Now buttons are on the voice OTP + DTMF pricing page.
Before you start: DLT voice registration
TRAI requires your voice header (caller ID) and your OTP call script to be registered and approved on the DLT platform before you send voice OTP calls. If your business entity is not yet registered with that operator, the operator charges a one-time DLT registration fee of ₹5,900 including GST. Our team helps you with the paperwork; read the DLT registration guide.
Integrate in minutes
Trigger a voice OTP from your backend with an HTTP request, the same way you send an SMS. API keys, parameters and response codes are in the developer API documentation.
Frequently asked questions
What is voice OTP?
Voice OTP is a one-time password delivered by an automated phone call instead of SMS. When the user answers, the system reads the code aloud, usually twice and digit by digit, and can ask the user to press a key to confirm.
How much does voice OTP cost in India?
SMSGatewayHub voice OTP packs cost from ₹0.30 per connected call (1,00,000-call pack) to ₹0.42 per connected call (10,000-call pack), exclusive of 18% GST, billed on a 30-second pulse with 1-year validity. Higher volumes are quoted separately.
Is DLT registration needed for voice OTP?
Yes. TRAI requires your voice header (caller ID) and the OTP call script to be registered and approved on the DLT platform before you send voice OTP calls. SMSGatewayHub helps you with this registration.
Does voice OTP work on DND numbers?
Yes. Voice OTP is a service (transactional) communication triggered by the user's own action, so it runs 24x7 on the service route and is delivered to DND/NCPR-registered numbers.
Can voice OTP be used as a fallback for SMS OTP?
Yes. A common pattern is to send the OTP by SMS first and, if the user has not verified within a set time (for example 30 seconds), place a voice OTP call automatically or when the user taps "Call me instead".
Add voice OTP to your app
Register free, get your API key and test SMS and voice OTP side by side.