Kroki vs Userstack
Same instrument, two spec sheets — measured, not claimed.
Kroki vs Userstack: common questions
Which is more reliable, Kroki or Userstack?
On our scheduled checks, Kroki leads on measured uptime — Kroki 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, Kroki or Userstack?
Userstack has the lower median latency in our checks — Kroki responds in 633 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 Kroki and Userstack need an API key?
Kroki needs no key, while Userstack requires a free API key. If you want to start calling without signup, reach for Kroki first.
Can I call Kroki and Userstack from the browser?
Yes — both Kroki and Userstack send CORS headers over HTTPS, so front-end code can fetch either directly with no backend proxy. That makes them easy to swap in a client-side app while you compare responses.
Are Kroki and Userstack free for commercial use?
Kroki 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.