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AZ511 vs NHTSA

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

APIAZ511NEW—NHTSANEW—
Uptime · 30d
Uptime · 90d—%—%
Uptime · 30d—%—%
P50 · ms——
P95 · ms——
AuthapiKeynone
CORSnoyes
HTTPSyesyes
Card requirednono
Commercial useunclearyes
Data licenseUnverifiedPublic domain (U.S. Government work)
Free tierFree tier — API key requiredFree, no key
Rate limitUnpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

AZ511 vs NHTSA: common questions

Which is more reliable, AZ511 or NHTSA?

On our scheduled checks, NHTSA leads on measured uptime — AZ511 at —% versus NHTSA 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 AZ511 and NHTSA need an API key?

NHTSA needs no key, while AZ511 requires a free API key. If you want to start calling without signup, reach for NHTSA first.

Can I call AZ511 and NHTSA from the browser?

Only NHTSA is browser-friendly — it returns CORS headers over HTTPS. AZ511 needs a server-side call or proxy, so factor that into which one fits a front-end project.

Are AZ511 and NHTSA free for commercial use?

AZ511 has unclear commercial terms, and NHTSA allows commercial use on its free tier. 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.