Ducks Unlimited vs PostalCodes

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

Uptime · 30d
Uptime · 90d99.02%99.02%
Uptime · 30d98.3%98.3%
P50 · ms8321030
P95 · ms22022594
Authnonenone
CORSyesno
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified
Free tierFree — limits not publishedFree — limits not published
Rate limitUnpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

Ducks Unlimited vs PostalCodes: common questions

Which is more reliable, Ducks Unlimited or PostalCodes?

Both are neck-and-neck — Ducks Unlimited and PostalCodes each measure 99.02% uptime over 90 days on our probe schedule. Reliability here is verified from our own scheduled checks; use the 30-day bars above to see which has been steadier lately.

Which is faster, Ducks Unlimited or PostalCodes?

Ducks Unlimited has the lower median latency in our checks — Ducks Unlimited responds in 832 ms versus PostalCodes at 1030 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 Ducks Unlimited and PostalCodes need an API key?

Neither needs a paid key — Ducks Unlimited is callable with no signup, and PostalCodes is callable with no signup. Both are quick to prototype with; rate limits still apply.

Can I call Ducks Unlimited and PostalCodes from the browser?

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

Are Ducks Unlimited and PostalCodes free for commercial use?

Ducks Unlimited has unclear commercial terms, and PostalCodes 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.