cdnjs is a free distributed JS library delivery service.
Google Maps is a web mapping service. It offers satellite imagery, aerial photography, street maps, 360° interactive panoramic views of streets, real-time traffic conditions, and route planning for traveling by foot, car, bicycle and air, or public transportation.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
PayPal is an online payments system that supports online money transfers and serves as an electronic alternative to traditional paper methods like checks and money orders.
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.
Vercel is a cloud platform for static frontends and serverless functions.
Zendesk is a cloud-based help desk management solution offering customizable tools to build customer service portal, knowledge base and online communities.