HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
libphonenumber is a JavaScript library for parsing, formatting, and validating international phone numbers.
Progressive Web Apps (PWAs) are web apps built and enhanced with modern APIs to deliver enhanced capabilities, reliability, and installability while reaching anyone, anywhere, on any device, all with a single codebase.
Stripe offers online payment processing for internet businesses as well as fraud prevention, invoicing and subscription management.
Unpkg is a content delivery network for everything on npm.