CloudFlare - Cloudflare is a global network designed to make everything you connect to the Internet secure, private, fast, and reliable.
AWS WAF - AWS WAF is a web application firewall that helps protect your web applications from common web exploits.
Amazon CloudFront - Amazon CloudFront is a content delivery web service.
ModSecurity - ModSecurity is an Open Source web application firewall developed by Trustwave's SpiderLabs.
KeyCDN - KeyCDN is a high-performance Content Delivery Network (CDN). Lowest price globally at $0.04/GB with HTTP/2 Support and free Origin Shield.
Barracuda Web Application Firewall - Barracuda Web Application Firewall offers security and DDoS protection against automated & targeted attacks.