Why Edge Caching Still Matters in 2026

By Marta Ellison · July 8, 2026 · Infrastructure

Every few years someone declares the edge cache obsolete: bandwidth is cheap, compute is fast, so why bother? Yet p99 latency keeps telling a different story. The round trip from a user in Sao Paulo to an origin in Frankfurt costs around 200 ms on a good day, and no amount of application optimisation can shave physics off the wire.

What changed is not whether to cache, but what. Modern stacks cache HTML shells and API responses with short TTLs and stale-while-revalidate semantics, turning the edge into a read-through layer rather than a static file dump. The tricky part is invalidation: purge APIs must be fast enough that editors never notice, and tagging strategies make that manageable at scale.

The practical advice stands: measure hit ratios per route, not globally. A 40% hit ratio on your hottest ten routes usually beats a 90% ratio diluted across thousands of cold paths. Cache deliberately, not enthusiastically.