A SaaS dashboard whose font files DDoS'd its own origin

A SaaS dashboard whose font files DDoS'd its own origin

A B2B analytics tool loaded four custom font weights and an icon sprite on every page. Cacheable, sure — but spread across 40 global POPs with no shield, each POP fetched the fonts independently on cold start. After every deploy with a fresh asset hash, 40 simultaneous cold fetches hammered the origin in Dublin.

Deploys were self-inflicting a mini origin storm.

What we changed: enabled origin shield through a single London node and set immutable cache headers (max-age 1 year) on hashed assets. Now one POP fetched each new font once, the shield held it, and the other 39 pulled from London — never origin.

Post-deploy origin requests dropped from ~1,200 in the first minute to 11. Font load time in Tokyo fell from 380ms to 22ms. The Dublin box stopped spiking on every release.

The number that mattered: cold-start origin fetches 1,200 to 11.