JP stands for Job Points, which are points earned after completing a job or mission in Grand Theft Auto Online. They are used to determine tiebreakers in playlists, specifically races. The default JP reward for completing a job is 15, but players can earn different amounts depending on their performance during the job. JP is reset to zero once a player leaves the game or swaps sessions. While RP (Reputation Points) is often confused with JP, they are distinct mechanisms that determine the course of the game within a lobby.