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Cartes.io vs Postcodes.io

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

APICartes.ioNEW—Postcodes.ioNEW—
Uptime · 30d
Uptime · 90d—%—%
Uptime · 30d—%—%
P50 · ms——
P95 · ms——
Authnonenone
CORSyesyes
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverified (open-source project; user-generated maps)Service MIT-licensed; postcode data license unverified
Free tierFree, no API key for public readFree — no key required
Rate limit60 req/window · 59 remainingUnpublished (no key; fair use)
In directory since2026-07-052026-07-05
operationalpartialdownno data

Cartes.io vs Postcodes.io: common questions

Which is more reliable, Cartes.io or Postcodes.io?

On our scheduled checks, Postcodes.io leads on measured uptime — Cartes.io at —% versus Postcodes.io 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 Cartes.io and Postcodes.io need an API key?

Neither needs a paid key — Cartes.io 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 Cartes.io and Postcodes.io from the browser?

Yes — both Cartes.io 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 Cartes.io and Postcodes.io free for commercial use?

Cartes.io 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.