serpstack vs Userstack
Same instrument, two spec sheets — measured, not claimed.
serpstack vs Userstack: common questions
Which is more reliable, serpstack or Userstack?
Both are neck-and-neck — serpstack and Userstack each measure 99.02% 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, serpstack or Userstack?
Userstack has the lower median latency in our checks — serpstack responds in 492 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 serpstack and Userstack need an API key?
Both ask you to authenticate — serpstack uses an API key and Userstack uses an API key. Each key is free to obtain; the Auth and Card-required rows above spell out the signup terms.
Can I call serpstack and Userstack from the browser?
Only Userstack is browser-friendly — it returns CORS headers over HTTPS. serpstack needs a server-side call or proxy, so factor that into which one fits a front-end project.
Are serpstack and Userstack free for commercial use?
serpstack 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.