How to use WhatsApp OTP for login & verification (securely and at scale)?

WhatsApp OTP (One-Time Password) has emerged as a preferred method for user verification over traditional SMS due to its speed, reliability, and security features. Unlike SMS, which can face delivery issues and security vulnerabilities such as SIM swapping, WhatsApp offers near-instant message delivery with end-to-end encryption and a familiar user interface. Implementing WhatsApp OTP involves using a secure backend, a verified Meta Business Account, and pre-approved message templates to ensure compliance with strict WhatsApp policies. This method not only enhances user experience by reducing friction in the authentication process but also provides developers with advanced analytics and fewer support issues. While scaling the OTP process, it is crucial to adhere to WhatsApp's rate limits and opt-in policies to maintain service reliability and avoid potential throttling. Prelude offers services to integrate and optimize WhatsApp OTP flows, ensuring fast and secure transactional messaging.