01
Choose the delivery channel
Select email, SMS, or WhatsApp for each send. Your application handles channel choice, consent, and any fallback user experience.
AUTHENTICATION WORKFLOWS
OTP verification for login and signup.
Add OTP-based login, signup verification, and step-up checks using email, SMS, or WhatsApp. Choose and configure the delivery channel your users need.
Channels this workflow engages
OTPSMSWhatsAppEmail
02
Verify on the server
Sendrin generates and hashes codes, checks expiry and verification attempts, and invalidates a code after successful verification.
03
Handle limits clearly
Build your UI around expiry, resend cooldowns, and rate-limit errors. Keep application keys on the backend and add your own abuse controls where needed.
- Generated codes
- 4–8 digits
- Expiry
- 1–60 minutes
- Setup
- API key + channel configuration
More by use case
INSTANT DEPLOYMENT
Login, signup, and step-up checks from one OTP API.
One API, every channel, full delivery visibility. Start free, no credit card required.