.app is a top-level domain (TLD) specifically designed for applications and software. It was introduced by Google in 2015 and is intended for developers and businesses to create a recognizable online presence for their apps. The .app domain is secure by default, meaning that all websites using this TLD must have an SSL certificate, ensuring that data transmitted between users and the site is encrypted. This domain is popular among tech companies and app developers because it clearly indicates the purpose of the website. By using a .app domain, businesses can enhance their branding and make it easier for users to find their applications online.