Do I have to invite my coworkers to my wedding?
No. Employment is not a relationship that produces a wedding invitation, and there is no etiquette rule that says otherwise — plenty of couples invite nobody from work and never have to explain it. The only rule that binds you is about shape rather than obligation: if you invite from a team, invite all of it or clearly fewer than half of it, because those are the two versions the people left out cannot count themselves in.
Should I invite my boss to my wedding?
Only if you would still be friends if neither of you worked there — the reporting line on its own is never a reason. Two things make it different from any other colleague: an invitation traveling up the reporting line asks a manager for a Saturday and a gift she cannot comfortably decline, and a manager at your wedding is known at the office by Monday. So decide the team first. If the team is not invited and the boss is, rank is the only reading available.
How do I invite some coworkers and not others?
Count the group that would hear about it — the standup, the lunch table, the group chat — and invite strictly fewer than you leave out. Three of nine is a friendship; five of nine is a list. Then ask the people you did invite, once, to keep it off Slack. If you cannot get under half without cutting someone you genuinely want there, invite the whole team instead: it is usually only three or four extra invitations.
Is it rude not to invite coworkers to your wedding?
No, and it is by far the most common choice. What reads as rude is inconsistency, not absence: inviting most of a team, inviting the manager and none of the team, or handing invitations out at the office where everyone can see who got one. A wedding with no work guests at all requires no reason, no apology and no announcement.
How do I tell a coworker they are not invited?
Once, plainly, and without a reason that can be argued with: "we're keeping it to family and a few people we've known forever — it's tiny." Then change the subject. Do not say you would have loved to invite them, do not offer a maybe, and do not explain it a second time. If it is a team you like, invite them to something that is not the wedding — drinks the week after costs an evening rather than sixteen seats.
Do I have to invite a coworker who invited me to their wedding?
No. An invitation you accepted was a nice day, not a contract, and reciprocity fades fast once the friendship is only a work one. Run the same test you would run on anyone: would you still see them if either of you left tomorrow? If yes, they go in as a friend and count in the team ratio like everyone else. If no, nothing is owed and nothing will be said.