CDNJS vs serpstack

Same instrument, two spec sheets — measured, not claimed.

Uptime · 30d
Uptime · 90d100%99.02%
Uptime · 30d100%98.3%
P50 · ms281492
P95 · ms9361442
AuthnoneapiKey
CORSyesno
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified
Free tierFree and open, no keyFree tier — key may be required
Rate limitUnpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

CDNJS vs serpstack: common questions

Which is more reliable, CDNJS or serpstack?

On our scheduled checks, CDNJS leads on measured uptime — CDNJS at 100% versus serpstack at 99.02% over 90 days. These are our own probe results, not provider claims; the uptime bars above show the day-by-day record for both.

Which is faster, CDNJS or serpstack?

CDNJS has the lower median latency in our checks — CDNJS responds in 281 ms versus serpstack at 492 ms (P50). Tail latency (P95) is in the table above; for most workloads the median is the number that shapes how the API feels.

Do CDNJS and serpstack need an API key?

CDNJS needs no key, while serpstack requires a free API key. If you want to start calling without signup, reach for CDNJS first.

Can I call CDNJS and serpstack from the browser?

Only CDNJS is browser-friendly — it returns CORS headers over HTTPS. serpstack needs a server-side call or proxy, so factor that into which one fits a front-end project.

Are CDNJS and serpstack free for commercial use?

CDNJS has unclear commercial terms, and serpstack has unclear commercial terms. We track service terms and the data license as separate fields — see the Commercial use and Data license rows above, and confirm both before shipping either in a paid product.