Check-In System

Offline Mode & Sync

How the scanner works without internet and synchronizes when connectivity returns.

3 min readUpdated 2025-01-13

Picture a kirtan hosted in a converted barn an hour outside cell coverage, or a sunrise meditation retreat where the lodge's wifi hasn't quite reached the check-in table. BrightStar's scanner is built for exactly these gatherings — events that ask for stillness and presence but happen in places connectivity forgets. This guide walks through how offline mode works, what it can and cannot verify while you're disconnected, and how everything reconciles once a signal comes back.

How does the scanner load ticket data before you lose signal?

The moment a scanner link is opened for the first time, BrightStar downloads everything it needs to keep working without internet: every ticket ID for the event and the attendee name attached to it. This is stored locally in the browser's IndexedDB storage — roughly 50KB for every 1,000 tickets, a small enough footprint that even a modest phone handles it without strain. Because this caching happens on first access, it's worth opening the scanner link at least once while you still have a connection, well before doors open, so the download is already finished by the time you're standing somewhere with no bars.

What can the scanner actually check when it's offline?

Once the cache is in place, an offline scan runs two checks: does this ticket ID exist in the local list at all, and has it already been marked scanned on this specific device. A clean result on both shows green for valid; a ticket already checked in on that device shows red for duplicate. What offline mode cannot do is ask the server whether the ticket has already been scanned somewhere else — that comparison only happens once connectivity returns, which is why the sync process and the conflict rules that follow matter as much as the scan itself.

What happens once the scanner reconnects?

When a scanner that's been working offline finds a signal again, BrightStar syncs it automatically, without anyone needing to tap anything:

  1. 1Scanner detects network availability
  2. 2Queued scans sent to server in a batch
  3. 3Server validates and records all scans
  4. 4Conflicts resolved through duplicate detection
  5. 5Updated ticket list pulled back to the cache
  6. 6Interface shows a Synced confirmation
  7. 7The whole process is automatic and transparent

How does BrightStar resolve conflicts when scans come back in?

Two situations come up often at events with patchy connectivity, and BrightStar has a defined answer for both. If two offline scanners check in the same ticket before either has synced, the first timestamp wins: whichever scan happened earliest is recorded as the valid check-in, and the later one is marked Already checked in once its device syncs. The other case is a ticket refunded while a scanner is offline — the scanner's cache doesn't know about the refund yet, so it may still show the ticket as valid at the door. Once that scanner syncs, though, the server rejects the scan and logs it as Scan attempted on invalid ticket, so there's a record even though the check-in itself doesn't stand. Neither situation can be caught by the device in the moment; both only resolve once it talks to the server again.

A little preparation before doors turns offline mode from a fallback into routine. It's worth remembering that offline mode can't tell if a ticket was scanned on another device — so for events where that matters most, keep one scanner online or run a single-scanner setup rather than several offline devices working the same door. Steps that help most:

Common questions

Can the BrightStar scanner work with no internet at the venue?

Yes. When a BrightStar scanner link is first accessed, all ticket IDs and attendee names are pre-cached to the browser's IndexedDB storage, so validation continues without connectivity. Offline, the scanner checks that the ticket ID exists in the local cache and has not already been marked scanned on that device, showing green for valid or red for duplicate.

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This front-loading matters because the moment you actually need offline mode — no bars, a full room waiting at the door — is the worst moment to discover the cache never downloaded. Opening the scanner link once while you still have signal, ideally before doors open, is what makes everything else in this guide possible. Without that first load, there is no local list to check against at all.

How much storage does the offline ticket cache use?

The BrightStar offline cache uses roughly 50KB per 1,000 tickets, stored in the browser's IndexedDB. That covers all ticket IDs and attendee names for the event, downloaded when the scanner link is first opened.

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That footprint scales in step with your guest list, so an event with 5,000 tickets uses roughly five times the space of one with 1,000 — still small next to what a typical phone or laptop browser has available. Because the cache holds ticket IDs and attendee names rather than anything heavier, it stays lightweight even for larger gatherings, which is part of why the scanner can run entirely from local storage once it has loaded.

What happens to offline scans once the internet comes back?

The BrightStar scanner detects when the network returns and sends queued scans to the server in a batch. The server validates and records all of them, resolves conflicts through duplicate detection, and pushes an updated ticket list back to the cache, after which the interface shows a Synced confirmation. The whole process is automatic and transparent to the person scanning.

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Because this sequence runs on its own, whoever is scanning doesn't need to watch for a signal or trigger anything manually — the moment the device reconnects, it quietly reports everything recorded while offline and pulls back an updated list. The Synced confirmation is the one thing worth actually watching for, since it's the signal that every check-in made offline has now reached the server and is reflected there.

What if two offline scanners scan the same ticket?

BrightStar resolves that conflict on sync by first timestamp wins. The earlier scan is recorded as the valid check-in and the second is marked Already checked in. This is why offline mode cannot detect in the moment that another device has already scanned a ticket.

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Because the decision is based on timestamp rather than which device happens to sync first, the outcome doesn't depend on network speed or luck — an early scan that syncs late still beats a later scan that syncs first, since the server compares when the scan actually happened. It's a reminder that at the door, a green light means the ticket looked unused locally, not that no one else has scanned it yet.

What happens if a ticket is refunded while the scanner is offline?

The offline cache will still show the ticket, but BrightStar's server rejects the scan when the device syncs. The attempt is recorded as Scan attempted on invalid ticket, so you have a record of it in the logs.

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This logged record matters even though the check-in itself doesn't stand: it gives you a trail showing a ticket was presented and scanned after it had already been refunded, rather than the attempt simply vanishing. It also means a scanner working offline can, for a stretch, keep showing tickets as valid that the organizer has already cancelled — another reason to sync periodically rather than only at the very end of the event.

How should I prepare for an event with poor connectivity?

BrightStar recommends pre-loading the scanner link while you still have a connection and testing offline mode before the event. Assign a dedicated scanner per entrance, sync periodically if wifi is available, watch the sync status indicator, and have a backup mobile hotspot ready. For high-security events, ensure internet connectivity or use a single-scanner configuration, since offline mode cannot detect a scan made on another device.

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Most of these steps exist to cover for the one thing offline mode genuinely can't do on its own: notice that another device already scanned a ticket. A dedicated scanner per entrance and periodic syncing shrink the window where that gap matters, and a backup hotspot gives you a way back online if wifi drops entirely. For events where a duplicate check-in would be a real problem, staying on a single scanner or keeping real connectivity is the safer route.

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