Voice OTP
Verification delivered by voice
When an SMS OTP doesn't land — filtered, delayed, or blocked — a voice call gets through. Add call-based verification as your primary channel or as the fallback that rescues conversions.
Request RatesVerification that completes
LIVE FLOWHigher completion where SMS struggles
Voice OTP bypasses SMS filtering and handset spam folders — particularly effective across South Asian and African destinations.
Built for apps and fintech
Login verification, transaction confirmation and account recovery flows, integrated through a simple API in days.
Smart fallback logic
Run SMS-first with automatic voice fallback, or voice-first for destinations where you know the data — you control the flow.
How voice OTP works
Your platform calls our API with a number and a code. We place a call over our direct voice routes and read the code aloud — or deliver it through the caller ID itself with flash call verification, where the user never has to answer. The result posts back to your system in real time.
SMS OTP vs voice OTP
SMS is cheaper per attempt; voice completes more often on hard destinations. The right answer for high-volume senders is usually both: SMS first, voice as an automatic fallback after a timeout. Senders using fallback flows typically recover a meaningful share of verifications that would otherwise be abandoned — each one a signup or a transaction saved.
Where it fits
- Fintech logins and transaction approval
- OTT and marketplace account verification
- Account recovery for users without data connectivity
- Destinations with aggressive SMS filtering
Frequently asked questions
What is flash call verification?
Instead of speaking the code, we place a call whose caller ID contains the verification digits. Your app reads the incoming number and verifies automatically — the user never answers, and the experience takes about two seconds. It suits Android apps with call-log permission.
How fast is the call placed after the API request?
Calls are placed immediately over our direct voice routes — the user is typically hearing the code within seconds of your request. The full result, including whether the call was answered, posts back to your webhook in real time.
Can SMS-to-voice fallback happen automatically?
Yes. The common pattern is SMS first, then an automatic voice call if no verification completes within your timeout. You set the timeout; we handle the switch. Fallback flows recover verifications that would otherwise be abandoned.
Which destinations benefit most from voice OTP?
Markets with aggressive SMS filtering or congested A2P routes — parts of South Asia, Africa and the Middle East in particular. If your SMS delivery reports show gaps in specific countries, those are the destinations to trial voice on first.
Related services
Ready to get your traffic moving?
Test routes in days. Talk to our Hong Kong team about rates, corridors and integration.