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CarAPI vs Transport for United States

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

APICarAPIHEALTHY70Transport for United StatesHEALTHY84
Uptime · 30d
Uptime · 90d100%100%
Uptime · 30d100%100%
P50 · ms12231093
P95 · ms22871963
AuthapiKeynone
CORSnoyes
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedData copyright transit agencies / Umo IQ
Free tierFree tier — API key may be required for productionFree — limits not published
Rate limitUnpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

CarAPI vs Transport for United States: common questions

Which is more reliable, CarAPI or Transport for United States?

Both are neck-and-neck — CarAPI and Transport for United States 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, CarAPI or Transport for United States?

Transport for United States has the lower median latency in our checks — CarAPI responds in 1223 ms versus Transport for United States at 1093 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 CarAPI and Transport for United States need an API key?

Transport for United States needs no key, while CarAPI requires a free API key. If you want to start calling without signup, reach for Transport for United States first.

Can I call CarAPI and Transport for United States from the browser?

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

Are CarAPI and Transport for United States free for commercial use?

CarAPI has unclear commercial terms, and Transport for United States 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.