Voice OTP: verification codes by phone call
Reach users that SMS and WhatsApp miss. A voice call reads the one-time password aloud, digit by digit and in the user's language, as a fallback when a text is not delivered or as the first choice for landlines and accessibility.
- 1Code requested
- 2WhatsApp or SMS sent
- 3No delivery or no entry
- 4Voice call placed
- 5Code read twice
- 6User enters code
Typical verification waterfall with voice OTP as the final step. Order and timings are set per use case.
Short answer
Updated
Voice OTP from OmniChannels.ai places an automated call that reads a one-time password aloud with text-to-speech, including Arabic. It reaches landlines and users whose SMS or WhatsApp code did not arrive. Voice is provisioned with our team rather than through public REST endpoints: we agree caller IDs, call flows and how your systems trigger calls and receive outcomes.
What voice OTP gives your verification flow
Codes read aloud
Text-to-speech reads the code digit by digit with pauses, repeats it, and can offer a key press to hear it again.
Arabic and English voices
Choose the language from the user's app or profile setting. Arabic text-to-speech reads the greeting and the digits in Arabic.
Fallback after SMS or WhatsApp
Trigger the call only when the first channel was not delivered or the code was not entered, so you pay for voice only when it is needed.
Landlines and feature phones
Voice reaches numbers that cannot receive SMS or WhatsApp, and users who prefer listening to reading.
Agreed caller IDs
We agree a recognisable caller ID and number ranges for each country, within local telecom rules.
Call outcomes to your systems
Your system triggers calls and receives outcomes through an integration we agree during setup, for example events sent to your webhook.
Your app keeps the code
Your backend generates, stores and checks the code. The platform only delivers it, so verification logic stays under your control.
Under your brand for resellers
Resellers can offer voice OTP under their own brand with the same white-label, multi-tenant setup as messaging.
Voice OTP compared with SMS and WhatsApp OTP
Most teams combine channels. The right order depends on your users, markets and fraud exposure.
| Item | Details |
|---|---|
| SMS OTP | Works on almost every mobile phone and is the usual first or second step. Needs a registered sender ID in many markets. |
| WhatsApp authentication | Copy-code, one-tap or zero-tap templates for users with WhatsApp. Charged by Meta per delivered message, passed through at zero markup. |
| Voice OTP | Reaches landlines and users whose message did not arrive, and helps accessibility. Usually priced per call duration, so best as the final step. |
| Flash call | Verifies a number with a short missed call. Some operators restrict or reprice it, so availability is confirmed per country. |
| Pricing | Voice OTP pricing is on request: contact sales for voice pricing for your destinations. Excludes taxes; your quote confirms the rate per destination. |
How to add voice OTP
Voice depends on caller IDs, number ranges and local telecom rules, so it is configured with you.
- 1
Scope countries and volumes
Tell us the destinations, expected daily and peak verification volumes and the languages you need.
- 2
Agree caller IDs
We agree the caller ID to present in each country and any numbers you already own.
- 3
Write the script
Keep it short: who is calling, the code read digit by digit, a repeat, and a warning never to share the code.
- 4
Integrate triggers and outcomes
Agree how your backend requests a call after SMS or WhatsApp fails and where call outcomes are sent.
- 5
Test, then go live
Calls go to your own verified numbers first; production routes switch on once compliance checks are complete.
When voice OTP makes sense
A good fit when
- A share of your users do not receive SMS codes reliably, and every failed sign-up costs you a customer.
- You verify landline numbers or serve users who prefer audio, such as older customers.
- You need Arabic and English verification calls in the GCC and the wider Middle East.
- You want a complete fallback chain: WhatsApp, then SMS, then voice.
Good to know before you start
- Voice is set up with our team. There are no public voice endpoints in the REST API and no instant self-serve access.
- Voice usually costs more per verification than SMS or WhatsApp, so most teams use it as a fallback.
- Voice verification attracts international revenue share fraud; use destination allow-lists, per-number rate limits and short call durations.
- If a call reaches voicemail, the code can be stored in the mailbox. Keep stronger methods for high-risk actions.
Voice OTP questions
What is voice OTP?
Voice OTP is a one-time password delivered in an automated phone call. A text-to-speech voice reads the digits, usually twice, and can offer a key press to repeat them. It works on mobiles and landlines and needs no app or data connection.
Is there a voice OTP API?
Voice is provisioned with our team rather than through public REST endpoints. During setup we agree how your systems trigger a call, for example after an SMS is not delivered, and where call outcomes are sent, such as your webhook. Messaging channels use the public REST API in the meantime.
When should I send the code by voice instead of SMS?
Use voice when the number is a landline, when the SMS or WhatsApp code was not delivered or not entered within your timeout, or when users need audio for accessibility. Triggering voice on a missing delivery or verification signal keeps costs down.
Can voice OTP calls be in Arabic?
Yes. Arabic text-to-speech reads the greeting and the code in Arabic. Pick the language from the user's app or profile setting, keep the script short and read the code digit by digit so numbers are pronounced clearly.
How much does voice OTP cost?
Voice is usually priced by call duration and destination, so voice OTP is priced on request: contact sales for voice pricing. Your quote confirms the rates for your destinations, excluding taxes.
Is voice OTP more secure than SMS OTP?
Not fundamentally. Both travel over the phone network, and a number can be ported, SIM-swapped or forwarded. Voice adds the voicemail risk. Use voice for reach and accessibility, and keep passkeys or authenticator apps for high-risk actions.
How do I stop fraud on voice verification?
Allow calls only to the countries you serve, limit attempts per number, per device and per IP address, keep calls short, and watch for spikes to unusual destinations. Ask us to review the controls for your traffic during setup.
Guides on this topic
- OmnichannelVoice OTP and Flash Call: When to Use Voice to Verify15 min read
- SMS & OTPOTP Messages on WhatsApp and SMS: Security, Delivery and Fraud9 min read
- SMS & OTPSMS Pumping Fraud: How AIT Works and How to Stop It9 min read
Explore more of the platform
Add voice to your OTP flow
Tell us your destinations, volumes and languages. We'll scope caller IDs, the Arabic and English scripts and the fallback trigger with your team.