They are published on the leetcode website. Here's a screenshot showing where to click [1].

LeetCode does have an "unofficial" API to get the problem of the day. Should work for previous days as well. This code worked last I tried [2].

[1] https://github.com/ebanner/daily-coding-challenges#leetcode

[2] https://github.com/ebanner/get-daily-leetcode-problem/blob/m...

It's a feature of the leetcode.com website. I actually can't find a URL that will directly link to the current day's problem, but you can open https://leetcode.com/problemset/ and select the current date in the calendar widget (at the top right on desktop, or by clicking the green calendar floating action button at the bottom right on mobile).

You can view the daily problem without logging in or creating an account.

Fair warning: today's daily problem is a "hard" difficulty and it is often worth skipping those or peeking at the solution. They can take a while to solve (often at least an hour) and/or rely on unusual tricks or data structures. I haven't solved this one yet so idk exactly what its deal is.