caldays vs The SMS Works API
Same instrument, two spec sheets — measured, not claimed.
caldays vs The SMS Works API: common questions
Which is more reliable, caldays or The SMS Works API?
Both are neck-and-neck — caldays and The SMS Works API 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, caldays or The SMS Works API?
caldays has the lower median latency in our checks — caldays responds in 149 ms versus The SMS Works API at 518 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 caldays and The SMS Works API need an API key?
caldays needs no key, while The SMS Works API requires a free API key. If you want to start calling without signup, reach for caldays first.
Can I call caldays and The SMS Works API from the browser?
Yes — both caldays and The SMS Works API 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 The SMS Works API free for commercial use?
caldays has unclear commercial terms, and The SMS Works API 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.