What Sites Are Free CDNs Good For? Check Quotas, Caching, and Usage Limits

The most appealing thing about a free CDN isn't just that it costs nothing—it's that there's almost no barrier to trying it: connect a domain, update DNS, enable the proxy, and your site can be up and running quickly.

For personal blogs, portfolios, open-source project documentation, and small sites that have just launched, this may indeed be the most suitable starting point. But “free now” and “zero long-term cost” are not the same thing.

Some free CDNs don't limit regular web traffic but do limit individual file size; some grant a fixed monthly amount of traffic and requests, after which you must upgrade or stop service; others only allow distribution of public software packages and are not suitable at all for hosting image sites, video, or downloadable files.

The more practical issue is that even if the free quota is sufficient, cache rules, logs, security features, support, and node coverage may not meet business requirements.

So, to determine whether a website is suitable for a free CDN, you shouldn't just ask “how many GB per month?” Instead, look at three conditions first:whether the content is easy to cache, whether traffic is predictable, and whether service interruptions are acceptable.

First, distinguish which kind of “free CDN” you're looking at

Many products say “free,” but the way they are free can be completely different.

If these concepts are not separated, later cost estimates are almost certain to be wrong.

For example, a trial that gives 100GB of traffic only means testing may be free; if the site consistently consumes 80GB per month, you'll still need to pay standard pricing after the trial ends. A public open-source resource CDN, even if it has no traditional monthly traffic bill, does not mean you can upload private files, installers, or commercial videos for long-term hotlinking.

Before choosing, open the official pricing page, terms of service, and limitations to confirm whether “free” is a long-term plan, a recurring allowance, or a one-time sign-up offer.

Which websites are usually suitable to start with a free CDN

Personal blogs, portfolios, and sites with infrequent content updates

These sites usually consist mainly of HTML, CSS, JavaScript, and images, with relatively simple page structures and little logged-in or personalized content.

If article images are compressed and monthly traffic is stable, a free CDN can often handle most static asset delivery. Even if some HTML pages are not cached by default, TLS termination, connection reuse, and static asset caching may still improve the visitor experience.

They also have an important characteristic: occasional configuration issues lasting a few minutes are usually acceptable losses. Site owners have time to read documentation and adjust DNS and cache rules themselves, and may not need immediate human support from the vendor.

Open-source project documentation and product information pages

Documentation sites have clear file versions, are usually rebuilt when updated, and often use hashed asset filenames, for example:

/assets/app.a8c932f1.js
/assets/docs.721bd011.css

Once filenames change, they can be cached long term, making it easy to achieve a high hit ratio without the problem of “the origin has updated, but the CDN is still returning old files.”

If the project is public, traffic is normal, and it doesn't rely on complex server-side sessions, a free CDN is very suitable for validating regional accessibility and the build-and-release workflow.

Newly launched MVPs, campaign preview pages, and test environments

While a product is still being validated, traffic is limited and requirements change quickly, so buying a complex enterprise CDN plan too early isn't cost-effective.

A free plan can first be used to validate:

• whether the domain and HTTPS are configured correctly;

• whether static assets can be cached;

• whether access speed in key user regions is acceptable;

• whether deployment, cache purge, and rollback processes run smoothly;

• which logging, security, and caching features the website actually needs.

But test environments also require attention to access permissions. Just because the CDN is free, don't expose internal admin pages, test APIs, or resources with sensitive data directly to the public internet.

Small business showcase sites

A corporate website with only a company introduction, product descriptions, contact information, and a few forms may also be suitable for a free CDN.

The key consideration isn't just monthly traffic, but the business loss caused by downtime. If the website is only an auxiliary showcase channel and has no online transactions or strict availability requirements for now, a free plan can be a starting point.

If all advertising, sales business cards, and customer entry points point to this one website, even with very low traffic, the requirements for stability and support response may already exceed a free plan.

Which websites should not choose a free CDN just because “traffic isn't high”

E-commerce, payment, booking, and membership businesses

Many requests on these sites relate to user identity, inventory, pricing, and order status. They not only need static asset acceleration, but also reliable WAF, bot management, rate limiting, logs, alerts, origin protection, and incident support.

More importantly, business losses are unrelated to traffic volume. With only a few hundred visitors a day but a high value per order, the loss caused by downtime or a caching error may be far greater than a year of CDN fees.

A free CDN can be used to cache public images, CSS, and JavaScript, but login, shopping cart, order, and user center pages should not be forcibly cached without sufficient testing.

Video, software installer, and large file download sites

Large files quickly consume free traffic quotas and may also trigger limits on single-file cache size, request duration, Range requests, or usage policies.

For example, according to Cloudflare's current official documentation, the maximum size per cacheable file on Free, Pro, and Business plans is 512MB, and the maximum request upload size on the Free plan is 100MB. Specific numbers may change in the future; before deployment, checkCloudflare default cache behavior and limitsfor the latest details.

Here you also need to distinguish “upload limit” from “cacheable file limit.” A user uploading a file to the website and a user downloading a file through the CDN are two different paths, so don't assume one number applies to both uploads and downloads.

If the business is mainly video playback, game patches, system images, or software downloads, prioritize checking:

• the maximum cacheable size per file;

• whether Range requests and range origin fetches are supported;

• whether the video or download content complies with the terms of service;

• whether the free traffic covers all regions;

• whether exceeding the quota results in billing, rate limiting, or service suspension;

• whether hot files may be purged, and whether they can be pre-warmed.

Websites prone to attacks

A free plan may provide basic DDoS mitigation and a few security rules, but that does not equal guaranteed mitigation bandwidth, dedicated scrubbing resources, customized policies, and human support during an attack.

Gaming, finance, trading platforms, controversial content sites, and websites that have suffered sustained HTTP flood attacks should first evaluate attack types, normal business peaks, origin hiding, origin authentication, and service commitments during attacks.

If the core requirement is “stay online during an attack,” you can't just look at whether the website says “DDoS protection.” You can also refer to“How to Choose a High-Protection CDN: What to Look at in Protection Capability, Nodes, and Testing Scope”to compare free basic protection and high-protection services with clearly defined boundaries.

Websites with high requirements for mainland China access quality

“Many global nodes” does not mean fast access across China Telecom, China Unicom, and China Mobile. Node location, network interconnection, cross-border links, domain ICP filing, and acceleration regions all affect the actual experience.

Some free CDNs perform well in North America and Europe, but users in mainland China may experience connection fluctuations, carrier differences, or cross-border link congestion. Whether a CDN is suitable cannot be judged only by the vendor's global node map; test with your own domain and real content by region.

If users are mainly from mainland China, you can first read “For Users Mainly in Mainland China, Which Regions and Carriers Should You Focus on When Choosing a CDN,” then decide whether a free global CDN is sufficient or whether you need a service with mainland nodes and coverage across the three major carriers.

Websites that need clear SLAs, audit logs, and human support

Free services usually do not provide the same SLA and support level for business as paid enterprise plans. When cache anomalies, false blocks, certificate issues, or regional outages occur, you may only be able to check documentation, community forums, or submit a low-priority ticket.

Healthcare, finance, government, enterprise SaaS, and businesses with compliance requirements may also need longer log retention, permission auditing, data processing agreements, and services in specified regions. These requirements cannot be measured by “is the free traffic enough?”

When looking at free quotas, don't just look at the number of GB of traffic

A complete free quota should be broken down into at least the following items:

Some platforms charge by traffic, some by requests, and others split CDN, WAF, DNS, logs, and edge computing into different products. The CDN itself having no bill does not mean the whole architecture won't incur costs.

For example, Amazon CloudFront currently offers a Free plan with a fixed monthly fee of $0. The official pricing page also lists monthly quotas for requests and data transfer, and clearly states that different tiers differ in features such as custom cache rules, logs, and SLA.

Because plans may be updated, actual selection should checkAmazon CloudFront official pricing and plan comparisonand not rely on an old screenshot for the long term.

Use a simple formula to estimate traffic

Assume one complete page visit transfers an average of 2MB of content from the CDN and there are 100,000 page visits per month:

预计下行流量 ≈ 平均每次传输量 × 页面访问次数
             ≈ 2 MB × 100,000
             ≈ 200 GB

This is only a rough estimate. It does not account for factors such as browser caching, duplicate assets, bots, preloading, failed retries, and video playback.

A more reliable approach is to count actual transfer volume from existing server logs or analytics platforms, and leave headroom for organic growth, search engine crawling, and campaign peaks. Don't directly extrapolate peaks from “how many visitors per day on average.”

Request counts may exceed quotas earlier than traffic

A page that is only 1MB, if it contains 80 small images, scripts, and API requests, may generate far more requests per open than the file size suggests.

Icon sites, API aggregation pages, and websites made up of many small files may have low monthly traffic but a very high request count. Conversely, a large file download site may have few requests but exhaust downstream traffic quickly.

When choosing a free plan, estimate both “how many GB” and “how many requests.”

Caching capability determines whether the free quota can truly be saved

A free CDN does not automatically cache all content after onboarding.

Different products have different default caching policies. Taking Cloudflare as an example, its official documentation states that by default it mainly determines cacheable content based on file extension, and HTML and JSON are not cached by default; when the origin returnsprivate,no-store,no-cache,max-age=0orSet-Cookiethe corresponding response may also not be cached.

For specific rules, seeCloudflare default cache behavior.

This means that for a site mainly composed of dynamic HTML and APIs, even after integrating a free CDN, origin request volume may not drop significantly.

To check caching, you can choose a public image and request the same URL repeatedly:

curl -sS -D - -o /dev/null \
  'https://static.example.com/images/test.jpg'

Focus on the cache status headers provided by the vendor,Age,Cache-Control,Expires,VaryandSet-Cookie. Different vendors may use different field names; don't make a hasty judgment based on one genericX-Cache.

For specific methods, refer to“How to Read CDN Cache Hits: Understanding HIT, MISS, and Age”. If you have just completed onboarding, you should also first follow “Has CDN Acceleration Taken Effect? Check This After Onboarding” to confirm the domain is no longer connecting directly to the origin.

Common caching feature limitations in free plans

Even if basic caching is available, advanced capabilities may still require payment:

• custom cache keys;

• caching by cookie, device, or request header;

• tiered caching and origin protection;

• cache tag purging;

• long-term cache retention;

• large file caching and pre-warming;

• real-time cache analytics;

• a finer-grained number of page rules or cache rules.
  

For an ordinary blog, these features may not be necessary; but for multilingual, e-commerce, API, and sites with complex login states, the lack of custom caching capabilities may become a bottleneck earlier than the free traffic quota.

Usage limits most easily overlooked in free CDNs

Content type restrictions

You need to confirm whether the service allows video, audio, software packages, proxy downloads, image hotlinking, and user-uploaded content. Some free products are positioned to accelerate normal web pages, not to act as unlimited-traffic file hosting services.

There is also a category of public CDNs aimed only at open-source software packages. They are suitable for referencing public JavaScript or CSS dependencies in web pages, but not for storing private corporate files, backups, paid resources, or arbitrary downloadable content.

Commercial use restrictions

Some free tiers allow both personal and commercial projects, while others are only for non-commercial projects, learners, or open-source communities. A company website cannot assume commercial use is allowed just because the product page says “Free.”

You should review the account entity, purpose, content licensing, fair use, and termination clauses in the terms of service, not just read the marketing page.

Traffic spikes and abnormal usage handling

After a website is shared by a popular community, traffic may grow dozens of times within a few hours; malicious crawlers and attacks can also generate large numbers of requests.

You need to know in advance:

• whether exceeding the free quota triggers automatic charges;

• whether a credit card must be bound;

• whether budget alerts or hard limits can be set;

• whether reaching the limit returns errors, rate limits, or automatically upgrades;

• whether attack traffic and requests blocked by WAF count toward the quota;

• whether the vendor may suspend the domain or account due to abnormal usage.
  

“No overage fees” and “unlimited service after exceeding the quota” are not the same concept either. A plan with no overage bill may control costs by limiting features, limiting usage, or requiring an upgrade.

Technical support limitations

Free users often rely on documentation and community. When a website is down, you may not be able to get immediate human troubleshooting.

If you are not familiar with DNS, certificates, caching, and origin configuration, you should also count operations time as a cost. A seemingly free solution may not be cheap for a commercial website if every incident takes half a day to troubleshoot.

Migration and export limitations

The more you use vendor-specific edge functions, image processing URLs, cache rules, or security expressions, the higher the migration cost.

Before enabling it, it's best to answer a few questions: Can DNS be switched back quickly? Can certificates be reissued? Is there a configuration list for cache rules? Can logs be exported? Does the origin allow the new CDN to fetch from it?

A free plan can serve as a starting point, but don't let it become an architecture you can't exit.

How to judge whether your website can use a free CDN

You can first run a small test that does not involve a long-term commitment.

Record the current baseline first

Before onboarding, save the DNS, TTFB, download time, status codes, and failure rates for key pages and static files. The test scope should cover key user regions, not just the site owner's office network.

Onboard only one subdomain that can be rolled back

For example, first usestatic.example.comfor images, CSS, and JavaScript; don't migrate all business domains on day one. This way, even if cache or certificate configuration goes wrong, it's easier to switch back to the original path.

Observe continuously for a complete business cycle

An ordinary content site should cover at least weekdays and weekends; an event website should cover a real promotion; a cyclical business should cover its own traffic peak.

Observe not just average speed, but also:

• P50 and P95 access latency;

• failure rates by region, carrier, and time period;

• cache hit ratio and origin traffic;

• 4xx, 5xx, and certificate errors;

• the rate at which the free quota is consumed;

• whether cache purging, log querying, and incident handling are convenient.
  

You can useCdnChart website speed testto observe resolved IPs, status codes, and timing at each stage across regions and carriers, then combine that with vendor monitoring and origin logs.

For how to choose a speed testing tool and record results, refer to “How to Choose a CDN Speed Test Site: Check Nodes, Metrics, and Result Records First.”

A more practical selection standard

Here, “suitability” is not a rating of any one CDN.

The same blog, if it has tens of millions of image requests per month, may not be suitable for a free plan; the same corporate website, if it is completely static, has stable traffic, and has a rollback plan, may also be able to use a free plan long term.

Frequently asked questions

Can a free CDN really be used free forever?

It depends on the specific model. A permanently free plan, a monthly free quota, and a limited-time trial are completely different.

Even if a plan exists long term, its feature scope, quotas, and terms of service may be adjusted. Before launch, save the pricing and rules at that time, and review the official pages regularly.

Is a free CDN enough for a personal blog?

Most personal blogs with compressed images and stable traffic can start with a free plan.

But check the speed in key user regions, whether HTML is cached by default, whether images and scripts hit cache, and how traffic spikes are handled.

Can a free CDN defend against DDoS attacks?

Some free plans provide basic DDoS mitigation, but that does not equal guaranteed mitigation bandwidth, Layer 7 policy tuning, dedicated scrubbing nodes, and human response.

Businesses that have been attacked or must stay online during an attack should evaluate against the standards of high-protection services.

Will a free CDN affect SEO?

A CDN itself does not directly affect SEO just because it is free.

What really needs attention is accessibility, status codes, HTTPS, redirects, caching errors, regional timeouts, and whether search engines can crawl reliably. Incorrectly caching 404s, intermittent 5xx errors, or regional inaccessibility may indirectly affect crawling and user experience.

What happens after the free quota is used up?

Different products may automatically bill, require an upgrade, limit features, rate limit, or suspend service.

Before use, confirm whether a payment method must be bound, whether budget alerts can be set, and whether there is a hard usage cap. Don't wait until traffic has already exceeded the quota to look for the rules.

When should you upgrade from a free CDN?

When the free quota is frequently near its limit, key cache rules cannot be implemented, logs are insufficient for troubleshooting, performance in key regions is unstable, or the loss from one incident is clearly higher than the paid cost, you should upgrade or re-evaluate your choice.

The truly suitable free CDN is not the one with “the most features” or “the largest advertised traffic,” but the one whose free scope just covers your current business while leaving room for future migration and upgrades. As long as the quota is clear, cache behavior is understandable, and usage limits are acceptable, a free plan can absolutely be a reliable starting point for a small website.