Two-factor authentication (2FA) improves both the strength of an authentication system and users' experience. ASP.NET Core provides a robust 2FA solution with Microsoft and Twilio resources to speed development. The Authy API, part of Twilio's Verify API, offers secure passwordless logins, one-time passwords via SMS or voice, soft token push authentication through Android or iOS apps, and more. To get started with ASP.NET Core 2FA using Twilio Authy, developers need a Windows 10 machine, a Twilio account, .NET Core 2.1.808 SDK, Visual Studio 2019, and knowledge of C# and .NET Core. The tutorial guides through setting up the Authy demo project, updating configuration files, creating the database, testing SMS authentication, voice authentication, and push authentication. With this guide, developers can build a secure ASP.NET Core application with Twilio Authy's advanced 2FA features.