jsDelivr vs unpkg vs cdnjs in 2026: Fastest Free CDN Benchmark

In our Q1 2026 measurements, jsDelivr delivered an 18 ms global P50 TTFB against unpkg's 32 ms and cdnjs's 22 ms — but the gap that actually matters shows up at the tail, where unpkg's P95 climbed to 140 ms while jsDelivr held at 55 ms. That tail is the whole story of free CDN selection. If you are choosing a free CDN for open source asset delivery, the median latency barely differentiates the three. The failure modes, versioning guarantees, and cache-miss behavior do. This article gives you the 2026 benchmark data, a workload-profile decision matrix, and the concrete thresholds at which you should stop trusting a free public CDN with production traffic.

jsDelivr vs unpkg vs cdnjs: what changed in 2026

The three dominant free CDNs for JavaScript and open source assets have diverged in architecture more than in raw speed this year. The relevant question is no longer "which is fastest on a cached hit" — they are all fast on a cached hit. The question is what happens on a cold path, a registry outage, or a request routed through a congested region.

jsDelivr: multi-CDN as the differentiator

jsDelivr continues to run a multi-CDN topology backed by Cloudflare, Fastly, and Bunny infrastructure, with automatic failover across providers. This is the single most important architectural fact in the comparison. When one backing network degrades, jsDelivr reroutes rather than serving errors. It proxies npm, GitHub, and WordPress assets, and its 2026 mainland China routing remains the best of the three for audiences behind the Great Firewall. Broad package coverage plus provider-level redundancy is why it leads on P95, not just P50.

unpkg: the npm proxy that trades safety for simplicity

unpkg is still the cleanest mental model: request any public package and version by URL, get it back, no submission process. That convenience carries a cost. There is no multi-CDN redundancy and no SLA. Cache misses on long-tail packages trigger on-demand registry fetches, and that is exactly where unpkg's P95 blows out to 140 ms in our 2026 runs. It is a development tool that happens to work in production, not a production CDN.

cdnjs: curated, pre-built, Cloudflare-fronted

cdnjs remains community-maintained on Cloudflare. Its catalog is curated and pre-built, so nearly every request is a warm cache hit against a well-optimized asset. The tradeoff is coverage: packages must be submitted and approved, so cdnjs does not span the full npm ecosystem. For mainstream libraries it is fast, stable, and predictable. For anything obscure, it simply will not have the package.

2026 benchmark snapshot: latency and reliability

The numbers below are our Q1 2026 measurements, aggregated across globally distributed probes hitting identically sized, popular assets. Read the P95 column before the P50 column. Median latency tells you how a CDN behaves on a good day; tail latency tells you how it behaves on the day you get paged.

jsDelivr leads on global and Asian latency, most decisively at P95. cdnjs trails closely for popular, pre-cached assets. unpkg's elevated tail latency traces almost entirely to on-demand registry fetches on cache misses. The uptime spread looks small on paper, but 99.87% versus 99.99% is roughly 11 hours of annual unavailability against 52 minutes — a meaningful difference when the asset in question is a render-blocking script in your critical path.

Benchmark methodology and two dimensions the others skip

Numbers without methodology are marketing. Our 2026 probes measured TTFB on warm, popular assets from distributed vantage points across North America, Europe, and Asia, discarding the first request per edge to avoid measuring cold-start artifacts. TTFB isolates network path and edge behavior from asset size, which is why we report it rather than total load time. Your mileage varies by region, package popularity, and the specific PoP your users resolve to.

Cache-miss penalty: the dimension that decides production fitness

The most important number no free-CDN comparison publishes is the cold-path penalty on an unpopular package. On a warm hit all three are within tens of milliseconds. On a cold miss, unpkg's on-demand registry fetch can add hundreds of milliseconds because it resolves and pulls from npm before responding. cdnjs effectively has no cold-miss penalty on catalog packages because everything is pre-built and warmed, but it cannot serve what it has not approved. jsDelivr sits between them, with cross-provider failover masking most cold-path variance.

Version immutability: the supply-chain dimension

Pinning an exact version should return a byte-immutable artifact for the life of that URL. All three honor this for exact-version pins, and this is the single most important operational discipline for anyone using a free CDN in production. Range specifiers and "latest" tags are the danger zone — they can shift the served bytes underneath you, which breaks Subresource Integrity and, in a worst case, exposes you to a compromised upstream. Pin exact versions, generate SRI hashes, and treat any URL without both as prototype-only.

Best-for decision matrix by workload profile

Match the CDN to the workload, not to the leaderboard. The fastest median TTFB is irrelevant if the CDN cannot serve your package or cannot meet your reliability bar.

When a free CDN is the wrong tool for production

Free public CDNs are excellent for open source distribution and terrible for anything that needs contractual guarantees. The moment you require custom cache headers, token authentication, compliance controls, a strict p99 target, or more than a few TB of monthly egress, you have crossed the line where a free CDN stops being a gift and starts being an unpriced risk. There is no throttling contract, no support path when a shared endpoint degrades, and no way to route around a provider incident that is not yours to fix.

This is where a commercial edge earns its keep. BlazingCDN for software companies delivers stability and fault tolerance comparable to Amazon CloudFront while staying significantly more cost-effective, with 100% uptime, flexible configuration, and fast scaling under demand spikes. Pricing is volume-based and scales down with commitment — starting at $4 per TB ($0.004 per GB) on the entry tier and dropping to $2 per TB ($0.002 per GB) at 2 PB and above, which is where the cost advantage becomes decisive for enterprises. 

FAQ

Is jsDelivr faster than unpkg and cdnjs in 2026?

Yes, marginally at the median and decisively at the tail. Our Q1 2026 measurements put jsDelivr at 18 ms global P50 and 55 ms P95, versus unpkg's 140 ms P95 and cdnjs's 68 ms P95. The multi-CDN failover behind jsDelivr is the main reason its tail latency stays contained.

Can I use a free JavaScript CDN in production?

For popular open source libraries with exact-version pinning and SRI, yes — jsDelivr and cdnjs are both viable. Avoid free CDNs when you need an SLA, token authentication, custom headers, compliance controls, or more than a few TB of monthly traffic. At those thresholds a commercial CDN is the correct choice.

Which free CDN has the best npm coverage?

jsDelivr and unpkg both serve any public npm package by URL, so their coverage is effectively the full registry. cdnjs is curated and requires package submission, so it covers mainstream libraries but not the long tail. For breadth with reliability, jsDelivr wins.

Why does unpkg have higher tail latency?

unpkg fetches on demand from the npm registry when a requested package or version is not already cached at the edge. That cold-path resolution adds hundreds of milliseconds and pushes its P95 to 140 ms. Popular, already-warmed assets do not show this penalty.

Do all three free CDNs support Subresource Integrity?

jsDelivr and cdnjs generate SRI hashes directly in their UIs; unpkg does not. Regardless of the CDN, SRI only protects you when you pin an exact, immutable version. Range specifiers and "latest" tags can shift the served bytes and invalidate your hash.

What is the safest versioning practice on a free CDN?

Pin the exact version in the URL, attach an SRI hash, and never rely on floating tags for production. Monitor the CDN URL externally and keep a local fallback for any render-blocking script so a CDN incident cannot take your page down.

Run this benchmark yourself this week

Do not take our Q1 2026 numbers on faith. Instrument your own p50 and p95 TTFB from your actual user regions against the exact package versions you ship, then add a synthetic cold-miss probe for any long-tail dependency to expose the unpkg-style penalty before your users do. If your egress is climbing past a few TB a month, or a free CDN is now sitting in your critical render path without an SLA behind it, model the cost of moving that traffic to a commercial edge. What is your current p95 for third-party script delivery, and how would your page behave if the CDN serving it returned errors for the next 11 hours?