The Calendar vs Tumblr
Same instrument, two spec sheets — measured, not claimed.
The Calendar vs Tumblr: common questions
Which is more reliable, The Calendar or Tumblr?
Both are neck-and-neck — The Calendar and Tumblr 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, The Calendar or Tumblr?
Tumblr has the lower median latency in our checks — The Calendar responds in 588 ms versus Tumblr at 208 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 The Calendar and Tumblr need an API key?
The Calendar needs no key, while Tumblr requires OAuth. If you want to start calling without signup, reach for The Calendar first.
Can I call The Calendar and Tumblr from the browser?
Yes — both The Calendar and Tumblr 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 The Calendar and Tumblr free for commercial use?
The Calendar has unclear commercial terms, and Tumblr 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.