Fastly, Inc. is an American company based in San Francisco, which describes itself as a cloud computing company. Fastly provides content delivery network services, image optimization, and load balancing services. Fastly's cloud security services include denial-of-service attack protection, bot mitigation, and a web application firewall. The Fastly platform is built on top of Varnish. As of March 2024, Fastly transfers 336 Tbps of data. Wikipedia