Anti-bot CAPTCHA widget that helps digitize books by providing snippets of books for people to enter the text for. Owned by Google.
Sleek, intuitive, and powerful mobile first front-end framework for faster and easier web development.
CloudFlare is a global CDN and DNS provider that can speed up and protect any site online.
This site uses the viewport meta tag which means the content may be optimized for mobile content.
PayPal is a American international e-commerce service that enables companies and individuals to send money and to accept payments without revealing any financial details.
Stripe is a developer-friendly way to accept payments online and in mobile apps.
Apple Pay payments on the web provides an easy and secure way to pay on websites in Safari. By using Touch ID or double-clicking Apple Watch, users can quickly and securely provide their payment, shipping, and contact information to check out with just one touch.
Websites that accepts payments with American Express.
nginx [engine x] is a HTTP server and mail proxy server written by Igor Sysoev.
Content Security Policy is best used as defense-in-depth, to reduce the harm caused by content injection attacks.
A canonical link element is an HTML element that helps webmasters prevent duplicate content issues by specifying the "canonical", or "preferred".