AlphaRank

AlphaRank is an online contest for painters: you upload a PNG or JPG, a vision model scores it on four criteria — composition, color, technique, presentation — each with written notes, and it lands on the daily, weekly and all-time boards next to each entrant's country flag.

The judging rules are not hard-coded: the four criteria live in Sanity documents, each with a weight, rule text, good and bad examples, and tweaks for different media. To change a rule you edit the document instead of the code, and the next entry is judged by the new rules. Work with a genuinely transparent background earns 10 extra points; but claiming transparency for what is really a white background loses presentation points.

No account is needed to browse: the leaderboards and the author's daily staff picks are public. To enter, sign in with a Google account, one entry per day, scoring takes 15 to 60 seconds and the page refreshes with the result. Each day the author picks a favorite painting and writes it up as a featured post.

One warning: the repository is currently private; the author has also written openly about an early mistake — entrants' email addresses were once stored in artwork documents while the dataset was publicly readable, exposing five addresses, later fixed by storing only a hash of the email instead of the address itself. Knowing that history helps before you submit.