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IsItWater vs Postali

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

APIIsItWaterNEW—PostaliNEW—
Uptime · 30d
Uptime · 90d—%—%
Uptime · 30d—%—%
P50 · ms——
P95 · ms——
AuthapiKeynone
CORSnoyes
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified
Free tierFree tier — API key requiredFree — no key, no signup, no monthly limit (per site)
Rate limitUnpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

IsItWater vs Postali: common questions

Which is more reliable, IsItWater or Postali?

On our scheduled checks, Postali leads on measured uptime — IsItWater at —% versus Postali 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 IsItWater and Postali need an API key?

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

Can I call IsItWater and Postali from the browser?

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

Are IsItWater and Postali free for commercial use?

IsItWater has unclear commercial terms, and Postali 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.