Pet Idle is a pet-adoption simulation game that requires a player use real-world actions and incremental play to succeed at adopting and caring for pets. The player initially receives one free pet and associated supplies needed to care for it. They can buy additional pets and supplies over time.
The game walks the player through everything they need to do to win. The player initially adopts a pet using the blue button marked with a paw print. They then name the pet, choose its gender and randomly select characteristics. They use a green button marked with a bowl to provide the pet with common pet-care products, including a water bowl, food bowl, ball toy, pet bathtub and pet bed.
The player can upgrade and level up items using coins and energy that their pet leaves behind on the floor when it's happy. They can determine their pet's happiness level by looking for emojis above it and checking a rainbow-colored happiness gauge near the upper left corner.
Pet Idle also allows the player to buy items to decorate the home where they keep the pets. They then use a construction mode to rearrange the pet supplies, furniture and other items.