Hey there, fellow Codeforces enthusiasts! I wanted to share with you a little project that I've been working on that I think you might find helpful. It's called CF-Daily, and it's a web extension that displays a couple of problem of the day on the problemset page of Codeforces.
There are 2 problems for each user to solve everyday- Global, which is common to every user where the rating of the problem doesn't have any limit, and Rating-wise, which suggests problem based on the rating of the user with a range of [user-rating - 200, user-rating + 200]
There is also a popup window when you click the icon of the extension which can show you the problems of any particular day (obv from the past).
All of this happened due to the powerful API of CodeForces
You can also contribute to it: Click Here
Let me know what you think of it, and if you have any feedback or suggestions, feel free to drop them in the comments section below.