How to Check In Guests at an Event: Running the Door

Last updated: July 2026

To check in guests at an event, open your check-in screen and scan each guest's QR code: green admits them and marks the ticket used, red means it was already scanned. A live attendance counter climbs as people arrive, and a shareable link lets several staff scan at once — with no app for guests.

That is the whole job of running a door: move a line quickly, admit each valid ticket exactly once, and always know your real headcount. This guide is about the door workflow and the guest list behind it — how to set up check-in, how to open multiple lanes safely, and what to do when a scan fails — rather than the mechanics of the camera itself. If you want the deeper how-the-scan-works explainer, see how QR code event check-in works from your phone.

How to check in guests at the door

Here is the full door workflow, from a finished guest list to the last person through:

1. Open the check-in screen. On any phone, open check-in for your event in the browser. Your guest list is already loaded — every issued ticket, live.
2. Scan the first guest's QR. Point the camera at the code on their phone or printout. It validates in one motion.
3. Read the light: green or red. Green means admit — the ticket is valid and is now marked used. Red means it was already scanned; you see who used it and when, so you can wave them on or ask a question.
4. Watch the counter move. Every green scan bumps your live attendance: checked-in up by one, remaining down by one. No tallying by hand.
5. Open more doors if the line grows. Share the check-in link with another staff member and they scan from their own phone — a second lane in seconds.
6. Fall back to manual entry when needed. If a camera won't focus, type or paste the ticket code. It runs the exact same check.

No hardware to rent, no terminal to configure, no line-item fee skimmed off each guest. Everything runs in a browser, and the guest list stays in sync across every phone scanning it.

How does the door read a ticket — green or red?

Each scan returns one of two clear results, designed so you barely have to look down. Green means the code is a valid, unused ticket: the guest is admitted and that ticket is immediately marked used. Red means the code has already been scanned — a screenshot someone forwarded, a photo of a printout, or a guest who genuinely already came in and went back to the car — and the screen shows who checked in on it and at what time.

That red-on-reuse rule is what separates real check-in from a decorative QR. A plain code just opens a link every time it's scanned, because nothing keeps score. Here, the guest list keeps a live record of every ticket — issued, valid, or used — so the second scan of any code is caught. A guest who "already came back from the car" is admitted on green the first time and flagged on red the second, with no argument at the door.

The result is a door that runs on a beep and a color, not on a staffer squinting at a clipboard for a matching name. You keep your eyes on the guest, glance at the light, and keep the line moving.

Can more than one person check guests in at once?

Yes — you can open several doors at the same time by sharing one check-in link with your staff. Each person opens the link on their own phone, with no login and no account, and starts scanning. Everyone is working the same guest list, so a ticket that is admitted at the front entrance is instantly marked used for the side door too.

This is the case a paper list handles worst. Two clipboards at two doors drift out of sync the moment the event gets busy: the same guest can be checked off on one list and walked in again on the other. A shared live record has one source of truth. Even the hardest edge case — two people showing the same code at two doors in the same instant — resolves cleanly: the admit-and-mark-used step is a single locked action, so exactly one scan wins and the other sees red. Two simultaneous scans of one ticket can never both get in.

Because the share link needs no account, it is also safe to hand out and easy to take back. If a staffer leaves early or a phone goes missing mid-event, rotate the link and the old one stops working immediately — without disturbing anyone still scanning on the current link. You control who can run your door, in real time.

Can I see live attendance as guests arrive?

Yes. The check-in screen shows your numbers updating with every scan: how many are checked in, how many are remaining, and how many tickets you issued in total. You never count heads by hand — each green admit moves the figures for you, across every phone scanning the same guest list.

You also get a breakdown by ticket type. If you issued General and VIP tiers, you can see how many of each has arrived — exactly what you need when it's time to open the VIP area, call capacity, or decide whether to keep the doors open. Live attendance turns a vague sense of "it's filling up" into a number you can act on mid-event.

After the last guest, that same data is a clean attendance record: who came, when they arrived, and by which tier. You can export the full guest list to CSV any time — the record is yours to keep, reconcile, or fold into next year's planning. For more on preparing and organizing that list before the doors open, see how to manage an event guest list.

What if a phone camera won't scan a ticket?

Type the code instead. Every ticket carries a short code alongside its QR, and the check-in screen has a manual-entry field that runs the exact same single-use check as the camera. A cracked lens, a dim doorway, a dim screen, a crumpled printout — none of them strand you at the door, because there is always a way to enter the code by hand.

Manual entry matters for a second reason: it works on any browser, even ones without camera scanning. So your fallback lane is never worse than your main lane — it just admits the same ticket, once, with the same green-or-red result. Keep it in mind for the occasional stubborn ticket rather than as your primary method; the camera is faster for a moving line, but the code field is your guarantee that no valid guest is ever turned away over a hardware hiccup.

One thing to plan for: check-in validates each scan against the server in real time, so you need a working connection at the entrance to enforce single use and keep attendance accurate. A phone's own mobile data is plenty — each validation is a tiny request. If your venue has a true dead spot, station the check-in phone where there's signal, and remember the manual code field runs the same server-side check, so it isn't an offline mode.

Running the door: QR check-in vs a paper guest list

A printed name list is the usual fallback, and it fails in predictable ways once a line forms. Here is how running the door on phone-based QR check-in compares to a clipboard.

At the door	Paper guest list	QR check-in
Admitting each guest once	Cross off a name, hope you did	Green admits, ticket marked used automatically
Screenshots / shared tickets	No way to tell	Red on reuse — shows who used it and when
Several doors at once	Lists drift out of sync	One live guest list, shared link, no login
Revoking a helper's access	Collect the clipboard	Rotate the link — old one dies instantly
Live headcount	Count by hand, hope it's right	Checked-in / remaining / issued, updating live
A camera that won't scan	—	Type the code — same single-use check

The list isn't just slower — it can't enforce single use or stay in sync across doors at all. A used-once code and a shared live record can.

Frequently asked questions

How do I check guests in at the door?

Open the check-in screen for your event on any phone and scan each guest's QR code. Green admits the guest and marks the ticket used; red means it was already scanned, with who used it and when. Your live attendance counter updates on every green scan, and if a camera won't focus you can type the ticket code by hand — the same single-use check either way.

Can more than one person scan at the same time?

Yes. Share one check-in link with your door staff and each person scans from their own phone, with no login. Everyone works the same live guest list, so a ticket admitted at one door is instantly used at the others — even two simultaneous scans of the same code can't both get in. Rotate the link any time to revoke access if a phone goes missing.

Can I see live attendance during the event?

Yes. The check-in screen tracks checked-in, remaining, and total issued, updating with every scan and broken down by ticket type. You never tally by hand, and after the event the same figures become an accurate attendance record you can export to CSV.

What if a phone camera won't scan a ticket?

Type the ticket code into the manual-entry field instead. It runs the identical single-use validation as the camera and works on any browser, so a cracked lens, a dim doorway, or a crumpled printout never leaves a valid guest stuck at the door. Keep it as a fallback; the camera is faster for a moving line.

Run your door on a beep and a color

Knowing how to check in guests at an event comes down to a fast, trustworthy door: scan each QR for a green admit or a red already-used, watch live attendance climb, open as many lanes as you need on one shareable staff link, and fall back to a typed code when a camera balks. No app for your guests, no clipboard to reconcile, no double entries slipping through.

You can set all of this up with MumenLabs Event Tickets — build your event and issue QR tickets for free, then publish once when you're ready to go live. If you're still planning the event, see how to sell tickets for a party or club night and how to add your logo to event tickets so they look the part. When the doors open, scan guests in and run the door from any phone — green means admit, and a used ticket is caught every time.