Here Is How to Tag Someone on Reddit, and Why Some Mentions Never Arrive

How do you tag someone on Reddit?

Learning how to tag someone on Reddit comes down to one habit: type u/ followed by their exact username in a comment, and Reddit turns it into a link to their profile and sends them a mention notification. The older form, /u/username with a leading slash, works the same way. Reddit's formatting guide says usernames are "automatically hyperlinked" and calls these links "userlinks."

1. Open the person's profile and copy the username exactly as it appears after /user/ in the address bar.
2. In your comment, type u/ and paste the name, with no space between them.
3. Post the comment and check that the name renders as a link. If it shows as plain text, the spelling or format is off.

The link and the notification are tied together. When Reddit added slashless autolinks, its r/changelog post warned that "using u/username will generate a username mention, so keep that in mind." The same post gives the escape hatch: write u\/username or u//username to name someone without linking or notifying them.

Usernames with hyphens work. Reddit's May 7, 2026 changelog fixed a bug where "username mentions were not working for usernames ending in a hyphen." Capital letters don't matter, since Reddit's code lowercases every mentioned name before looking it up.

When does a Reddit mention notify the person?

A mention notifies the person only when they have mention notifications on, can see the community, have not blocked you, and your comment is visible. Reddit does not publish these rules in its help centre. They come from the monitor_mentions function in Reddit's open-source code, last pushed to the reddit-archive/reddit repository in October 2017, which checks each condition in turn and silently skips the notification when one fails.

Situation	Notification sent in Reddit's 2017 code
Normal comment, person has mentions on	Yes
Person turned mention notifications off	No
Comment is in a community the person can't view	No
Person has blocked you	No
Your comment was removed as spam or deleted	No
You mentioned yourself	No
Person already gets a reply notification for the same comment	No, to avoid a duplicate
Comment mentions more than three usernames	No, for anyone named in it

The settings side is documented. Reddit's article on opting in or out of notifications says the Notifications tab shows "a list of all the available notifications" with a toggle for each, and its email preferences article lists mentions under "Activity on Reddit that are about you." The same notifications article warns that "most notifications disappear after 7 days," so an unanswered mention does not wait in the inbox forever.

The spam row matters if your account is new. A comment caught by the spam filter never triggers a mention, which is one more symptom to check alongside the signs of a Reddit shadowban.

How many people can you tag in one Reddit comment?

Tag three people or fewer, because Reddit's open-source code dropped every mention in a comment that named more than three users. The setting is butler_max_mentions = 3 in the code's example.ini, and the function that sends mentions reads: "If more than our allowed number of mentions were passed, don't highlight any of them." A comment naming four people notified none of them, not the first three.

Reddit has not published the current limit, and the live site runs code Reddit no longer open-sources. The safe practice follows the old rule. If you need to reach five people, split them across two comments, or tag the two or three who most need to see it.

Duplicates don't count twice. The code collects mentioned names into a set, so writing u/alex twice in one comment counts as one mention.

Does editing a comment add or remove a tag?

Editing works both ways in Reddit's 2017 code. The mention handler listened for both new comments and the comment_text_edited event, so adding u/username in an edit sent the notification then. Removing a name in an edit called unnotify on that person, which took the mention back out of their inbox.

How is an r/ link different from a u/ mention?

An r/subreddit link points readers to a community and notifies nobody, while u/username notifies the person you name. Reddit's article on community mentions says typing r/YourCommunityName "will automatically create a hyperlink," and warns that using it in unrelated threads "may be seen as spam."

Typing a subreddit's name doesn't ping its moderators either. Reddit's 2017 code counted only links starting with /u/ as mentions, and the community mentions article describes an r/ link only as a hyperlink. Reddit's list of Developer Platform apps includes one called Mod Mentions "to get notified when a moderator is mentioned in the community," an app a mod team installs for itself. To reach a mod team, send modmail.

Can you tag someone in a Reddit post or in chat?

You can write u/username in a post, but Reddit's 2017 code only sent mentions from comments. Its mention queue was bound to two events, new_comment and comment_text_edited, so a name in a post body became a link without a notification. Post titles don't render links at all. Reddit's help centre does not say whether posts notify today. If the person has to see it, tag them in a comment under your own post, which the code handled.

Chat works differently. Reddit's chat help articles, including How to use Reddit Chat, describe no mention or tagging feature. A chat already goes straight to the person, provided their chat request setting allows it. Reddit lets each redditor accept chat requests from "Everyone, Accounts older than 30 days or Nobody," and sets accounts of users under 18 to Nobody by default.

Where you write u/username	Link	Notification
Comment	Yes	Yes, under the conditions above
Comment edit that adds the name	Yes	Yes, in the 2017 code
Post body	Yes	Not in the 2017 code; current behaviour undocumented
Chat message	Not documented	Not documented; chat already reaches the person directly

Four ways to reach someone on Reddit

Comment with u/usernameLinks the name and notifies the person when the conditions above are met

Comment under your own postSends the mention that a name in the post body did not send in the 2017 code

ChatGoes straight to the person if their chat request setting allows it

ModmailReaches a mod team, which an r/ link never does

What if someone mentions your product without tagging anyone?

Reddit notifies an account only when its own username appears as a u/ link, so a post that names your product, your company or a competitor sends you nothing. Someone writing "has anyone tried your tool for this?" in a subreddit you never joined is the mention you want, and Reddit has no alert for it. You can look for those posts by hand with Reddit search, sorted by new.

RedReplier watches for them instead. RedReplier monitors Reddit, X, Bluesky, Facebook and Hacker News for your brand, product and keyword phrases and ranks each match by buyer intent. Matches land on your RedReplier dashboard within minutes of a post or comment going live, and email alerts go out as digests on a cadence you set per keyword, from hourly to daily. RedReplier drafts a reply, and you review, edit and post it yourself. Set it up for Reddit brand monitoring and keep u/ tags for the people you want to bring into a thread.

Frequently asked questions

How do you tag someone in a Reddit comment?

Type u/ followed by their exact username, such as u/spez, with no space. Reddit links the name to their profile and sends them a mention notification if their settings allow it. /u/username with a leading slash works too.

Does the person get notified when you tag them on Reddit?

Yes, when they have mention notifications on, can see the community, haven't blocked you and your comment isn't filtered as spam. If any of those fail, Reddit's 2017 code skipped the notification without telling you. The link still appears in your comment either way.

How many users can you mention in one Reddit comment?

Three in the last code Reddit published. Reddit's open-source code set butler_max_mentions = 3 and sent no notifications at all when a comment named more than three users. Reddit has not published a current figure, so keep each comment to three tags.

Do mentions work in Reddit posts?

A u/username in a post renders as a link, but Reddit's 2017 code only sent mention notifications from comments. Reddit's help centre does not document whether that has changed. Tag the person in a comment under the post to be sure the mention goes through.

How do you write a username on Reddit without notifying the person?

Escape the slash. Reddit's r/changelog post on autolinking says to write u\/username or u//username if you "don't want to generate a link & mention." The name then shows as plain text.

Does tagging a subreddit notify its moderators?

No. Reddit's help centre describes an r/subreddit link only as a hyperlink to the community, and Reddit's 2017 code counted only u/ links as mentions. Anyone who needs the mod team should send modmail.

Why is my Reddit mention not working?

First check that the name renders as a link. If it shows as plain text, the spelling or the u/ format is off. If it is a link but nothing arrives, check the four causes in Reddit's 2017 code: the person turned mention notifications off, blocked you or can't see the community, or your comment was filtered as spam. Reddit's 2017 code skipped the notification without telling the sender.

Can you tag the same person twice in one Reddit comment?

You can, but it gains nothing. Reddit's open-source code collected mentioned names into a set, so writing u/alex twice counted as one mention. It also means a repeat does not push you toward the three-name limit.

Does editing a comment to add a username send a notification?

In Reddit's 2017 code it did. The mention handler listened for the comment_text_edited event, so a name added in an edit notified that person. Removing a name in an edit took the mention back out of their inbox.

How long does a Reddit mention stay in someone's notifications?

Reddit does not list a lifetime for mention notifications. Its help centre says how long notifications stay available "depends on their type, ranging from 1 to 365 days," and that "most notifications disappear after 7 days." If the message matters, follow up within the week.