uno online is played with a deck of 108 cards, comprising of four colors: red, blue, green, and yellow, along with special action cards. The objective of the game is to be the first player to discard all of their cards. Each player is dealt seven cards, and the remaining cards are placed facedown in a draw pile. The top card from the draw pile is revealed to form the discard pile.

Players take turns, matching the top card of the discard pile by either color, number, or symbol. For instance, if a blue "7" is shown, the next player can play a blue card or any card with the number seven. Special action cards such as Skip, Reverse, and Draw Two add layers of complexity, allowing players to skip turns, change the direction of play, or force opponents to draw additional cards. The notorious Wild and Wild Draw Four cards grant players the power to change the color in play or make the next player draw four cards, respectively.