How to Verify an OTP Securely on Your Server (With Code Examples)
Ten rules for verifying one-time passwords on your server, from HMAC hashing and expiry to attempt limits and bot protection, with Node.js and PHP examples.
OTP for NRI Customers: How to Verify Users Who Live Abroad
How to deliver OTPs to NRI customers on Indian and foreign numbers, which channel works in each case, and WhatsApp OTP rates for popular NRI countries.
WhatsApp OTP vs SMS OTP in India: Cost, Delivery and When to Use Each
WhatsApp OTP and SMS OTP compared for Indian users: price per OTP, DLT and template setup, delivery status and reach, plus a formula for cost per verified user.
DLT Registration for OTP SMS in India: A Step-by-Step Guide
What to register on DLT before sending OTP SMS to Indian numbers: entity, sender ID and OTP template, with an example template and the common reasons for rejection.