Edge computing
Edge computing runs code on CDN nodes, as close as possible to the user: personalization, redirects, and tests handled in milliseconds, without round-trips to the origin.
In practice
Practical web uses: instant rewrites and redirects, security headers, lightweight geo-adaptation, form protection. The constraint: a restricted environment — no persistent database. Used well, edge gives a global site the responsiveness of a local one, without multiplying servers.