PostalCodes vs Postcodes.io

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

Uptime · 30d
Uptime · 90d99.02%100%
Uptime · 30d98.3%100%
P50 · ms103033
P95 · ms2594328
Authnonenone
CORSnoyes
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

PostalCodes vs Postcodes.io: common questions

Which is more reliable, PostalCodes or Postcodes.io?

On our scheduled checks, Postcodes.io leads on measured uptime — PostalCodes at 99.02% versus Postcodes.io at 100% over 90 days. These are our own probe results, not provider claims; the uptime bars above show the day-by-day record for both.

Which is faster, PostalCodes or Postcodes.io?

Postcodes.io has the lower median latency in our checks — PostalCodes responds in 1030 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 PostalCodes and Postcodes.io need an API key?

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

Only Postcodes.io 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 PostalCodes and Postcodes.io free for commercial use?

PostalCodes 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.