The prefix “u/” begins Reddit usernames in Reddit style.
Writing a username with “u/” identifies a person’s Reddit account, such as u/spez. Reddit’s brand terminology describes the prefix as an abbreviation of “username,” making it the user-focused counterpart to “r/,” which identifies a subreddit or community.
The notation is especially common in links, posts, credits, and discussions about Reddit participants. It helps readers distinguish a person from a place: u/example refers to an account, while r/example refers to a community. A user’s profile may contain posts and comments made across multiple subreddits.
The prefix does not mean that every Reddit URL or display name must always be written that way. It is a conventional Reddit-style form, and people may also refer to someone by an ordinary display name. Another common mistake is reversing the two prefixes: “u/” is for users, while “r/” is for communities. Reddit users are commonly called redditors, although “Reddit user” is also standard.