Artifact Power

Artifact Power is used to access traits from an artifact. Artifact Power is earned through engaging in most types of play and can spend this to unlock a unique tree of traits traced upon the form of their Artifacts, enhancing their abilities. The rate at which a player gains Artifact Power was increased with Artifact Knowledge that could have been improved with items like Artifact Research Notes.

Since the 8.0.1 pre-patch, the only artifact using the Legion Artifact Power system is the Underlight Angler while the Heart of Azeroth automatically grants the Azerite to power the Heart of Azeroth instead of having to manually right-click each item to obtain the Artifact Power.

Artifact Power Cap

 * The total Artifact Power cap was based on the total amount of AP, not on number of ranks purchased. Once you have enough AP to buy your 54th rank, you'll no longer be able to add additional AP, regardless of whether you actually buy that final rank or not.
 * There was no daily cap.