User Agent Lookup API vs Userstack
Same instrument, two spec sheets — measured, not claimed.
User Agent Lookup API vs Userstack: common questions
Which is more reliable, User Agent Lookup API or Userstack?
On our scheduled checks, User Agent Lookup API leads on measured uptime — User Agent Lookup 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, User Agent Lookup API or Userstack?
User Agent Lookup API has the lower median latency in our checks — User Agent Lookup API responds in 426 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 User Agent Lookup API and Userstack need an API key?
User Agent Lookup API needs no key, while Userstack requires a free API key. If you want to start calling without signup, reach for User Agent Lookup API first.
Can I call User Agent Lookup API and Userstack from the browser?
Only Userstack is browser-friendly — it returns CORS headers over HTTPS. User Agent Lookup API needs a server-side call or proxy, so factor that into which one fits a front-end project.
Are User Agent Lookup API and Userstack free for commercial use?
User Agent Lookup 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.