Postali vs SLF
Same instrument, two spec sheets — measured, not claimed.
Postali vs SLF: common questions
Which is more reliable, Postali or SLF?
On our scheduled checks, SLF leads on measured uptime — Postali at —% versus SLF at —% over 90 days. These are our own probe results, not provider claims; the uptime bars above show the day-by-day record for both.
Do Postali and SLF need an API key?
Neither needs a paid key — Postali is callable with no signup, and SLF is callable with no signup. Both are quick to prototype with; rate limits still apply.
Can I call Postali and SLF from the browser?
Yes — both Postali and SLF 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 Postali and SLF free for commercial use?
Postali has unclear commercial terms, and SLF 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.