Using WhatsApp as a fallback for SMS OTP
When SMS is slow or fails, the same OTP is delivered over WhatsApp — usually in under a second.
Most Indian smartphone users have WhatsApp, and WhatsApp OTPs arrive faster than SMS on an average day. Using WhatsApp as a first or fallback channel is the single biggest OTP-latency win for most apps.
How it works
- You send one /v2/otp/send request. We try your preferred channel first.
- If the primary channel doesn't deliver in your configured window (default 7s), we automatically send the same code over the fallback channel.
- The user sees whichever arrives first. The other is silently cancelled when the code verifies.
- You're only billed for the channel that actually delivered.
WhatsApp OTP is billed at the Authentication rate (₹0.1700 per conversation), usually cheaper than SMS in bulk.
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