Bright Sky (DWD) vs GrünstromIndex

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

Uptime · 30d
Uptime · 90d99.02%73.5%
Uptime · 30d98.3%73.3%
P50 · ms6561072
P95 · ms33494119
Authnonenone
CORSyesyes
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified
Free tierUnlimited, no key, no credit cardFree under fair-use policy
Rate limitUnpublishedFair-use (paid tiers for higher limits)
In directory since2026-07-052026-07-05
operationalpartialdownno data

Bright Sky (DWD) vs GrünstromIndex: common questions

Which is more reliable, Bright Sky (DWD) or GrünstromIndex?

On our scheduled checks, Bright Sky (DWD) leads on measured uptime — Bright Sky (DWD) at 99.02% versus GrünstromIndex at 73.5% 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, Bright Sky (DWD) or GrünstromIndex?

Bright Sky (DWD) has the lower median latency in our checks — Bright Sky (DWD) responds in 656 ms versus GrünstromIndex at 1072 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 Bright Sky (DWD) and GrünstromIndex need an API key?

Neither needs a paid key — Bright Sky (DWD) is callable with no signup, and GrünstromIndex is callable with no signup. Both are quick to prototype with; rate limits still apply.

Can I call Bright Sky (DWD) and GrünstromIndex from the browser?

Yes — both Bright Sky (DWD) and GrünstromIndex 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 Bright Sky (DWD) and GrünstromIndex free for commercial use?

Bright Sky (DWD) has unclear commercial terms, and GrünstromIndex 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.