Why SMS Still Matters in MFA: A Pragmatic Guide for Modern Authentication

SMS continues to play a critical role in multi-factor authentication (MFA) by serving as a practical, accessible second factor that bridges security and user inclusivity. Despite criticisms about its security vulnerabilities, such as SIM swapping and phishing, SMS-based authentication remains effective in reaching a vast array of users across different devices and environments, especially where other MFA methods are not feasible. Regulatory frameworks like 10DLC in the U.S., DLT in India, and GDPR in Europe have improved the reliability and accountability of SMS delivery by enhancing transparency and traceability, thus addressing many security concerns. While not flawless, SMS MFA significantly reduces the risk of account takeovers and credential-based attacks by blocking common attack vectors, making it an invaluable layer in a broader, layered security strategy that includes app-based authenticators and passkeys. Companies like Prelude.so enhance this security by providing a multi-channel, compliant verification infrastructure that integrates SMS, WhatsApp, and Email to ensure seamless and secure authentication flows.