PM2.5 Open Data Portal vs RainViewer

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

Uptime · 30d
Uptime · 90d—%—%
Uptime · 30d—%—%
P50 · ms
P95 · ms
Authnonenone
CORSnoyes
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified (attribution requested)
Free tierFree — no API keyFree — limits not published
Rate limitUnpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

PM2.5 Open Data Portal vs RainViewer: common questions

Which is more reliable, PM2.5 Open Data Portal or RainViewer?

On our scheduled checks, RainViewer leads on measured uptime — PM2.5 Open Data Portal at —% versus RainViewer 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 PM2.5 Open Data Portal and RainViewer need an API key?

Neither needs a paid key — PM2.5 Open Data Portal is callable with no signup, and RainViewer is callable with no signup. Both are quick to prototype with; rate limits still apply.

Can I call PM2.5 Open Data Portal and RainViewer from the browser?

Only RainViewer is browser-friendly — it returns CORS headers over HTTPS. PM2.5 Open Data Portal needs a server-side call or proxy, so factor that into which one fits a front-end project.

Are PM2.5 Open Data Portal and RainViewer free for commercial use?

PM2.5 Open Data Portal has unclear commercial terms, and RainViewer 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.