XL Candy is a resource in Pokemon Go that allows players to level up their Pokemon beyond the original Level 40 cap, all the way to Level 50. It is a special type of Pokemon Candy that is individual to each specific Pokemon species. You can start earning XL Candy when you reach Trainer Level 31. There are several ways to get XL Candy in Pokemon Go, including catching unevolved Pokemon, catching evolved, Legendary, or Mythical Pokemon, successfully catching a Raid boss, hatching eggs, and converting regular Candy into XL Candy. Once you have XL Candy, you can use it to level up your Pokemon beyond Level 40. To do this, you need to give your Pokemon XL Candy, which can be done as soon as they are over Level 40. You need 296 XL Candy to fully max out a Pokemon.