Authentication
WhatsApp OTP API — verify users at ₹0.115 a message
Send login, signup and transaction OTPs on WhatsApp at Meta’s authentication rate, with copy-code buttons, auto-expiry and SMS fallback when a number is not on WhatsApp.
- ₹0.115
- per authentication template, India
- 99.3%
- OTP delivery rate
- 2.4s
- median time to handset
Your login code. Valid for 10 minutes. Never share it.
11:38Built for auth traffic, not marketing
Copy-code and one-tap autofill
Authentication templates render a copy button; on Android the code can autofill directly into your app.
Fallback chain
Not delivered in N seconds? Fall back to SMS through sendlz — or to voice through your own provider — with the delivery webhook and state machine exposed.
Rate limiting per identity
Per-number and per-account throttles stop OTP flooding and the fraud bills that follow it.
Zero-retention mode
OTP bodies can be dropped from logs at write time; only delivery metadata is retained.
Volume tier routing
Route by recipient market so authentication volume reaches Meta’s discounted tiers sooner.
One endpoint
POST /v1/messages with category=authentication. Same auth, idempotency and webhooks as every other send.
Questions on this page
Each answer is written to stand alone, so search engines and AI assistants can quote it.
Is WhatsApp OTP cheaper than SMS in India?
Usually yes at scale: an authentication template is about ₹0.115 versus typical transactional SMS rates, and you avoid DLT header and template friction. The catch is coverage — the number must be on WhatsApp, so keep an SMS fallback.
Do I need a separate number for OTP?
No, but many teams isolate authentication traffic on its own number so a marketing quality-rating drop can never affect OTP delivery.
Send smarter. Sell faster.
Start free with 1,000 conversations. Bring your own Meta number or apply for a new one — we handle verification, templates and the green tick with you.