MiniMoth vs Clerk: OTP Pricing for Indian Developers

If you’re building for Indian users, phone OTP is the auth flow they already trust — email/password and social login convert worse. But most auth providers price OTP as an SMS add-on built for a US-first product, and that shows up fast once you check the actual per-message cost for Indian numbers.

The actual numbers

	Per OTP (India)	Free tier
MiniMoth	₹0.35	₹50/month (~142 OTPs)
Firebase Phone Auth	₹0.84	10 SMS/day
Clerk	₹8.40	None

Firebase’s number comes from its $0.01/SMS India rate after the first 10 free SMS/day. Clerk’s comes from its $0.10/SMS international SMS rate — Clerk doesn’t have India-specific SMS pricing, so international rates apply.

At 1,000 OTPs a month, that’s roughly ₹350 on MiniMoth versus ₹840 on Firebase and ₹8,400 on Clerk. The gap isn’t a rounding difference — it compounds with every OTP you send, and OTP volume tends to scale with your user base, not your revenue.

Why the gap exists

Clerk and Firebase are full identity platforms — OTP is one auth method among many (social login, magic links, MFA, org management). SMS is metered through a general-purpose messaging pipeline that isn’t tuned for India specifically, and DLT compliance (the TRAI-mandated sender registration required to send SMS to Indian numbers at all) is left to you or passed through at a markup.

MiniMoth only does one thing: phone OTP for Indian numbers. It’s TRAI DLT-registered directly, sends OTP via WhatsApp first (which doesn’t require DLT registration at all, since it goes through Meta’s Cloud API) and falls back to SMS automatically if WhatsApp fails. You’re never charged for an OTP that wasn’t delivered on either channel — the charge is reversed automatically to your credits balance if both channels fail.

What you don’t have to build

Beyond price, the OTP-specific parts of MiniMoth’s API save you from building:

• Rate limiting per phone number (send and verify)
• Session management with access + refresh token rotation
• DLT sender registration and carrier approval paperwork
• WhatsApp-first delivery with automatic SMS fallback

If you’re already deep in Clerk or Firebase for other identity features (org management, social login, MFA) and only want to swap the OTP/SMS piece, MiniMoth’s REST API is two endpoints — POST /v1/otp/send and POST /v1/otp/verify — so it drops in alongside whatever else you’re using rather than requiring a full auth migration.

See the full pricing breakdown or the quickstart to send your first OTP.