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RSQ API vs Userstack

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

APIRSQ APIHEALTHY91UserstackHEALTHY93
Uptime · 30d
Uptime · 90d100%99.02%
Uptime · 30d100%98.3%
P50 · ms783443
P95 · ms13873029
AuthnoneapiKey
CORSyesyes
HTTPSnoyes
Card requirednono
Commercial useunclearunclear
Data licenseUnverifiedUnverified
Free tierFree — limits not publishedFree tier — API key required
Rate limitUnpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

RSQ API vs Userstack: common questions

Which is more reliable, RSQ API or Userstack?

On our scheduled checks, RSQ API leads on measured uptime — RSQ API at 100% versus Userstack at 99.02% 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, RSQ API or Userstack?

Userstack has the lower median latency in our checks — RSQ API responds in 783 ms versus Userstack at 443 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 RSQ API and Userstack need an API key?

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

Can I call RSQ API and Userstack from the browser?

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

Are RSQ API and Userstack free for commercial use?

RSQ API has unclear commercial terms, and Userstack 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.