Chessdle is a multiplayer mate race: the same chess position opens on everyone's screen and whoever finds the mating move first wins the round. That is the difference from every other chess puzzle game. You are not solving a daily puzzle alone, you are racing your friends over the same position at the same time.
How it works
Open a room or join one with a code, and everyone gets the same position. You play the side to move and make the mating move on the board. Mate-in-1, mate-in-2 and mate-in-3 puzzles are mixed, and the line above the board says which one you got. If the final move has more than one mate, any of them wins.
Scoring rewards order: first to find the mate takes +3, second +2, third +1. Solve it on your first attempt and you get a +2 bonus, so accuracy matters as much as speed.
The puzzle pool
Puzzles come from the Lichess Open Database (CC0, public domain). There are 4,000 in total across three mate lengths: 1,500 mate-in-1, 1,500 mate-in-2 and 1,000 mate-in-3.
Every puzzle is uniqueness-verified, meaning exactly one first move leads to mate. Popularity and rating filters keep them from being either trivial or unreasonable. With a pool this wide, seeing the same position twice is very unlikely.
Tips
Count the king's escape squares first. Few escape squares usually means mate-in-1.
Look at the heavy pieces. Most mates finish with a queen or rook, so check those lines before anything else.
Do not dismiss sacrifices. In mate-in-2 and mate-in-3 the first move is often a piece sacrifice that looks absurd.
Do not rush. A wrong move costs you the round and the first-attempt bonus with it.