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Callook.info vs CustomGPT.ai

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

APICallook.infoNEW—CustomGPT.aiNEW—
Uptime · 30d
Uptime · 90d—%—%
Uptime · 30d—%—%
P50 · ms——
P95 · ms——
AuthnoneapiKey
CORSyesyes
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverified (data from public FCC ULS records)Unverified
Free tierFree — limits not publishedFree tier — API key required
Rate limitUnpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

Callook.info vs CustomGPT.ai: common questions

Which is more reliable, Callook.info or CustomGPT.ai?

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

Do Callook.info and CustomGPT.ai need an API key?

Callook.info needs no key, while CustomGPT.ai requires a free API key. If you want to start calling without signup, reach for Callook.info first.

Can I call Callook.info and CustomGPT.ai from the browser?

Yes — both Callook.info and CustomGPT.ai send CORS headers over HTTPS, so front-end code can fetch either directly with no backend proxy. That makes them easy to swap in a client-side app while you compare responses.

Are Callook.info and CustomGPT.ai free for commercial use?

Callook.info has unclear commercial terms, and CustomGPT.ai 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.