Introducing Login Approvals

This post introduces 'Login Approvals,' a new opt-in security feature that implements two-factor authentication using SMS codes sent to a user's mobile phone. It highlights the engineering effort, including intern contributions, to balance security with usability, opting for SMS over app-based or hardware tokens for broader accessibility. The feature aims to protect user accounts from unauthorized access by requiring verification from new or unrecognized devices, with options to save trusted devices and recover access if a phone is lost.