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ISO 3166-2 API vs Postcodes.io

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

APIISO 3166-2 APIHEALTHY84Postcodes.ioHEALTHY100
Uptime · 30d
Uptime · 90d100%100%
Uptime · 30d100%100%
P50 · ms105633
P95 · ms2865328
Authnonenone
CORSyesyes
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedService MIT-licensed; postcode data license unverified
Free tierFree — limits not publishedFree — no key required
Rate limitUnpublishedUnpublished (no key; fair use)
In directory since2026-07-052026-07-05
operationalpartialdownno data

ISO 3166-2 API vs Postcodes.io: common questions

Which is more reliable, ISO 3166-2 API or Postcodes.io?

Both are neck-and-neck — ISO 3166-2 API and Postcodes.io each measure 100% 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, ISO 3166-2 API or Postcodes.io?

Postcodes.io has the lower median latency in our checks — ISO 3166-2 API responds in 1056 ms versus Postcodes.io at 33 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 ISO 3166-2 API and Postcodes.io need an API key?

Neither needs a paid key — ISO 3166-2 API is callable with no signup, and Postcodes.io is callable with no signup. Both are quick to prototype with; rate limits still apply.

Can I call ISO 3166-2 API and Postcodes.io from the browser?

Yes — both ISO 3166-2 API and Postcodes.io 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 ISO 3166-2 API and Postcodes.io free for commercial use?

ISO 3166-2 API has unclear commercial terms, and Postcodes.io 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.