# What is a rotating barcode?

A rotating barcode is one whose value changes on a timer rather than staying fixed. Fidella wallet passes use one so that a screenshot or a photo taken over somebody's shoulder stops working within minutes. Scanning the live pass is unaffected.

Source: https://fidella.app/glossary/rotating-barcode
Last reviewed: 2026-08-30

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A loyalty barcode that never changed would be a permanent key to an account.
Anyone who captured it could keep using it.

## How each wallet handles it

Google Wallet computes the rotating value on the device itself. Apple Wallet has
no equivalent, so Fidella refreshes the pass in the background on a regular
cadence instead. The practical difference is that an Apple pass left unopened
for a while may take a moment to catch up.

## Scanning allows for drift

A code that has only recently rotated is still accepted for a window afterwards.
That tolerance exists because phones throttle background refreshes, and a
customer whose pass is a few minutes behind should not be turned away.