Glossary
CDN
Meaning and details
A CDN copies your files to the edge. Images, CSS, JavaScript and video live on servers in dozens of cities, and each visitor downloads them from the nearest one, cutting round-trip latency from hundreds of milliseconds t...
CDN meaning
A content delivery network: geographically distributed edge servers that cache and serve your static assets close to each visitor.
What is CDN?
A CDN copies your files to the edge. Images, CSS, JavaScript and video live on servers in dozens of cities, and each visitor downloads them from the nearest one, cutting round-trip latency from hundreds of milliseconds to tens. Cloudflare, Fastly, Bunny and the CDN layers built into Vercel and Netlify are the common names, and for most indie products a CDN arrives nearly free, either as the default of your hosting platform or as the free tier of a proxy like Cloudflare.
Why it matters to an indie builder: latency is a conversion tax. Studies repeatedly show measurable drop-off as page load climbs past two seconds, and the cheapest milliseconds you will ever buy are geographic. The second gift is offloading: when a page hits the front page of Hacker News, origin servers die, while a CDN absorbs the spike at the edge because 95 percent of the traffic is cacheable assets. The CDN is the difference between a viral moment and an outage story.
A concrete example: a SaaS with a marketing site in one European region serves a 1.8MB hero image. A visitor in Buenos Aires waits 900ms for it, plus 300ms for the bundle, total render north of 1.4s, and bounce on mobile climbs. Putting the assets behind a CDN drops the image fetch to 130ms from a São Paulo edge and the bundle to 90ms; render lands under 600ms. Same code, same image, one DNS change, and the improvement is largest exactly where the users furthest from the origin live, which is most of the planet.
Common mistakes: caching HTML aggressively and shipping stale pages (cache assets long, HTML short or not at all, and purge on deploy), no cache headers at all, which makes the CDN pass through instead of serve, skipping image optimization before adding a CDN, shipping a 2MB photo through a fast pipe is still shipping a 2MB photo, and forgetting the cache-key basics, versioned filenames or query strings, so deploys leave half the world on yesterday's JavaScript. The hosting blocks on IndieBoot include platforms where this entire layer is configured correctly by default.