SLF vs Zippopotam.us
Same instrument, two spec sheets — measured, not claimed.
SLF vs Zippopotam.us: common questions
Which is more reliable, SLF or Zippopotam.us?
Both are neck-and-neck — SLF and Zippopotam.us 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, SLF or Zippopotam.us?
SLF has the lower median latency in our checks — SLF responds in 213 ms versus Zippopotam.us at 219 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 SLF and Zippopotam.us need an API key?
Neither needs a paid key — SLF is callable with no signup, and Zippopotam.us is callable with no signup. Both are quick to prototype with; rate limits still apply.
Can I call SLF and Zippopotam.us from the browser?
Yes — both SLF and Zippopotam.us 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 SLF and Zippopotam.us free for commercial use?
SLF has unclear commercial terms, and Zippopotam.us 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.