Build a One-Time Password-Based Login System using Go and Twilio

The guide provides a comprehensive walkthrough for building a One-Time Password (OTP) based login system using Go and Twilio, aiming to enhance security by adopting passwordless authentication. It outlines the prerequisites, such as having Go 1.22, a Twilio account, access to a MySQL database, and basic Go knowledge. The system involves setting up a Go application, managing sensitive information through environment variables, and creating a MySQL database schema to store user details. Dependencies like Twilio's Helper Library for Go, GoDotEnv, and Go MySQL Driver are installed to facilitate SMS sending and database interactions. The application logic is implemented to handle user registration, login, and OTP verification using bcrypt for password hashing and Twilio for OTP transmission. It operates through an HTTP server, utilizing gorilla/mux for routing, and ensures security by logging OTPs in the console if Twilio is not configured. The guide also emphasizes testing the application and suggests future enhancements like using Redis for OTP storage and implementing rate limiting for added security.