Fastly is an American cloud computing company based in San Francisco that provides a programmable edge cloud platform, including Content Delivery Network (CDN) services, security solutions like DDoS protection and bot mitigation, image optimization, and load balancing. Its platform enhances web and app performance, delivers real-time insights, and allows for developer-friendly, agile DevOps practices through its fully software-defined network and WebAssembly-based Compute@Edge platform.