Cheesecake Labs, a development shop, built their SMS user verification app in less than a day using Python and Django, allowing users to quickly verify their phone numbers with a 6-digit pin-code. The app uses Twilio's API to send SMS messages and validate phone numbers. Marcelo Salloum, an iOS developer, created the feature as his first Twilio hack, aiming to provide a verification method that didn't require log-in credentials. The code is based on Django models and uses Twilio's client library to send SMS messages, with features like re-sending logic for users requesting another verification code.