UK Carbon Intensity vs Website Carbon

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

Uptime · 30d
Uptime · 90d100%100%
Uptime · 30d100%100%
P50 · ms78937
P95 · ms1948166
Authnonenone
CORSyesno
HTTPSyesyes
Card requirednono
Commercial useyesunclear
Data licenseCC BY 4.0 (per API docs)Unverified
Free tierFree — no API keyFree keyless byte-based /data endpoint
Rate limitUnpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

UK Carbon Intensity vs Website Carbon: common questions

Which is more reliable, UK Carbon Intensity or Website Carbon?

Both are neck-and-neck — UK Carbon Intensity and Website Carbon 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, UK Carbon Intensity or Website Carbon?

Website Carbon has the lower median latency in our checks — UK Carbon Intensity responds in 789 ms versus Website Carbon at 37 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 UK Carbon Intensity and Website Carbon need an API key?

Neither needs a paid key — UK Carbon Intensity is callable with no signup, and Website Carbon is callable with no signup. Both are quick to prototype with; rate limits still apply.

Can I call UK Carbon Intensity and Website Carbon from the browser?

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

Are UK Carbon Intensity and Website Carbon free for commercial use?

UK Carbon Intensity allows commercial use on its free tier, and Website Carbon 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.