OTP Verification via
Voice Calls
Deliver verification codes through automated phone calls with text-to-speech. Reaches landlines, works without internet, and supports 30+ languages.
Why Voice for OTP?
Reaches Landlines
Voice calls work on any phone — landlines, feature phones, and smartphones alike.
No Internet Required
Unlike WhatsApp or email, voice calls only need a phone connection.
Accessibility
Ideal for visually impaired users or those who struggle reading small text on screens.
SMS Fallback Built-In
If the call isn't answered, automatically fall back to SMS delivery.
How It Works
Call API
Send a message with channel 'voice' and your verification text.
Auto Call
We call the user's phone and read the code using text-to-speech in their language.
User Verifies
User hears the code, enters it in your app. Language auto-detected from country code.
Simple Integration
Send voice OTP codes with a single API call.
import Zavudev from '@zavudev/sdk';
const zavu = new Zavudev({
apiKey: process.env["ZAVUDEV_API_KEY"],
});
// Send voice OTP — language auto-detected from country code
const message = await zavu.messages.send({
to: '+14155551234',
channel: 'voice',
text: 'Your verification code is 1 2 3 4 5 6'
});
// Or specify language explicitly
const messageEs = await zavu.messages.send({
to: '+56912345678',
channel: 'voice',
text: 'Su código de verificación es 1 2 3 4 5 6',
voiceLanguage: 'es-ES'
});
console.log('Status:', message.status);Voice OTP Pricing
Voice calls are billed per minute from your prepaid balance. Rates vary by destination country.
Per Minute Rates
| Country | Starting from |
|---|---|
| United States | $0.01/min |
| United Kingdom | $0.014/min |
| India | $0.014/min |
| Mexico | $0.021/min |
| Brazil | $0.035/min |
| Chile | $0.035/min |
OTP calls typically last 15-30 seconds. A 30-second call to the US costs ~$0.005.
View PlansVoice OTP Features
Auto Language Detection
Language is automatically detected from the recipient's country code. Or specify it manually.
Natural Text-to-Speech
High-quality TTS voices in 30+ languages. Codes are read digit-by-digit for clarity.
Delivery Tracking
Track call status via webhooks — queued, sent, delivered, or failed.
Supported Languages
Voice OTP supports 30+ languages with automatic detection.
English, Spanish, Portuguese, French, German, Italian, Japanese, Korean, Chinese, Arabic, Hindi, Turkish, Dutch, Polish, Russian, and more.
Common Use Cases
Ready to Verify with Voice?
Start sending voice OTP calls in minutes. Works on any phone, any country.