Free CDN providers give you edge caching, meaning a copy of your static content served from a data center near the visitor instead of your single origin server, at no cost up to some limit. What they typically withhold: an origin shield (a layer that protects your origin from a stampede of requests when the cache misses), custom SSL certificates on the true free tier, fine-grained cache control, and support beyond a community forum. None of that makes free CDN tiers bad — it makes them a specific trade worth understanding before wiring one in front of a site that could have a CDN built into its hosting already.
The search results for this phrase are almost all vendor comparison pages, either enterprise CDN companies comparing themselves to each other on features nobody on a free tier gets, or listicles naming five providers with a line of marketing copy each. Neither explains what free costs you in capability, or that a lot of static hosting already includes CDN behavior without you configuring one separately.
Table of contents
- What a CDN actually does, in one paragraph
- The shapes ‘free’ actually comes in
- What’s capped, and what’s simply missing
- When a static host with a CDN built in is simpler
- When you still want a standalone CDN
- Reading a free CDN’s terms before you commit
- How this fits the rest of the stack
- FAQ
What a CDN actually does, in one paragraph
A content delivery network caches copies of your static assets — images, CSS, JS, and sometimes full HTML pages — at edge locations physically closer to visitors than your origin server. A request that would otherwise cross an ocean instead gets answered from a data center down the road, which cuts latency and takes load off the origin for anything cacheable.
It does nothing for content that has to be generated fresh per request — a personalized dashboard, an authenticated API response — unless you configure specific caching rules for it, which most free tiers do not expose.
The shapes ‘free’ actually comes in
Three different things get called a free CDN, and they are not equivalent.
- A permanently free tier of a paid CDN. Usually capped on bandwidth and requests, with the CDN company’s own branding or limits on customization, designed to convert you to a paid plan once you outgrow it.
- A CDN bundled into a broader platform, like a static hosting provider’s built-in edge caching. Not sold or marketed as a CDN on its own; it is just how the platform serves your files.
- A genuinely free, ad- or donation-supported CDN, rarer, usually smaller-scale and aimed at open-source or community projects rather than commercial traffic.
What’s capped, and what’s simply missing
The caps are usually visible on the pricing page: a monthly bandwidth ceiling, a request count, a limited number of points of presence compared to the paid tier. What’s missing is less visible until you need it:
- Origin shield. Without one, a cache miss at multiple edge locations simultaneously hits your origin all at once instead of being deduplicated into a single request. Small sites rarely notice; a sudden traffic spike on a free tier is exactly when this matters most and is least likely to be available.
- Custom SSL on your own domain. Some free tiers only support the CDN’s own subdomain or a shared certificate, pushing custom-domain HTTPS to a paid plan.
- Cache invalidation control. Purging a stale asset instantly, rather than waiting out a fixed TTL, is often a paid feature.
- Support beyond documentation and a community forum.
When a static host with a CDN built in is simpler
If the project is a static site — built from a repository, no server-side process — a static host that already serves through a CDN by default removes the entire evaluation above. There is no separate CDN account to configure, no origin-shield question to research, and no bandwidth cap to track in a second dashboard alongside your hosting bill.
On RunxBuild, a static site includes 120GB of bandwidth a month served from the platform’s edge, then $0.10/GB after that, with custom domains and certificates handled as part of the same deploy — no separate CDN sign-up, no separate certificate to manage on top of it. The CDN and content delivery guide covers the general mechanics in more depth.
When you still want a standalone CDN
A dedicated CDN in front of an existing server still earns its place for a few specific situations: your origin is a VPS or a dynamic application you cannot move off, you need edge compute or advanced routing logic a static host does not offer, or you are already deep into one CDN provider’s ecosystem for other services and consolidating makes sense.
In those cases, evaluate the free tier the same way you would evaluate free hosting anywhere: check the bandwidth cap against your real traffic, confirm custom-domain SSL is actually included at the tier you are looking at, and treat the absence of an origin shield as a real limitation, not a footnote.
Reading a free CDN’s terms before you commit
The terms page usually answers the questions the pricing page does not:
- What happens at the bandwidth cap — a hard stop, a slowdown, or a surprise bill for overage.
- Whether commercial use is allowed at all on the free tier, since some genuinely free CDNs are scoped to open-source or non-commercial projects only.
- How caching interacts with a build-and-deploy workflow — does a new deploy automatically invalidate the old cached version, or does it require a manual purge you might forget.
None of these are dealbreakers on their own. They are the difference between a free CDN that quietly does its job and one that surprises you the first time traffic actually spikes.
How this fits the rest of the stack
A free CDN is a reasonable choice for a lot of projects, as long as the cap and the missing pieces — origin shield, custom SSL, cache control — are ones you checked rather than assumed. For a static site, the simpler path is often not adding a CDN at all: static sites on RunxBuild serve through the platform’s own edge with bandwidth included, so there is nothing separate to configure or outgrow. If you are comparing that against a standalone CDN in front of an existing server, the RunxBuild hosting calculator puts the bandwidth cost on the same screen, and the dashboard is where the custom domain gets pointed either way.
Useful related references:
- CDN Content Delivery: What It Actually Does for Your Bill and Your Latency
- Netlify’s CDN: How the Edge Network Actually Serves a Site, What It Caches, and What It Costs When Traffic Arrives
- DDoS Protection CDN: What It Actually Stops and What Still Gets Through
- Static sites on RunxBuild
FAQ
Is a free CDN good enough for a small website?
Usually, yes, if your traffic sits comfortably under the bandwidth and request caps. The gap shows up in what’s missing rather than what’s capped: no origin shield for traffic spikes, sometimes no custom-domain SSL, and limited cache control, none of which matter until the site suddenly gets busy.
What’s the catch with free CDN tiers?
The catch is usually not the bandwidth cap, which is often generous enough for a small site. It is the missing features: no origin shield to absorb a traffic spike, custom SSL sometimes reserved for paid tiers, and support limited to documentation and a community forum instead of a real channel.
Do I need a separate CDN if my static host already has one?
No, and adding one usually adds complexity without benefit. A static host serving through its own edge network already gives you the latency benefit of a CDN; layering a second one in front just adds another cache layer and another dashboard to check.
What is an origin shield, and why does it matter for free CDNs?
It is a layer that deduplicates simultaneous cache misses across edge locations into a single request to your origin, instead of every edge hitting the origin at once. Free tiers often skip it, which matters most exactly when you need it most — a sudden traffic spike.
Can I use a free CDN with my own custom domain?
Depends on the provider and tier. Some free CDN plans only support HTTPS on the provider’s own subdomain and push custom-domain SSL to a paid plan. Check this specifically before committing, since it is one of the most common gaps between what a free tier implies and what it delivers.