caldays vs Slack
Same instrument, two spec sheets — measured, not claimed.
caldays vs Slack: common questions
Which is more reliable, caldays or Slack?
On our scheduled checks, Slack leads on measured uptime — caldays at —% versus Slack 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 caldays and Slack need an API key?
caldays needs no key, while Slack requires a free API key. If you want to start calling without signup, reach for caldays first.
Can I call caldays and Slack from the browser?
Yes — both caldays and Slack 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 caldays and Slack free for commercial use?
caldays has unclear commercial terms, and Slack 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.