Proximity beacons use Bluetooth Low Energy technology to detect nearby mobile devices and extract meaning from offline interactions. Beacons can provide location data at different scales, from whether someone is within a retail park to precisely where they are within a store. Beacon data includes the Received Signal Strength Indication (RSSI) which indicates distance from the beacon. Implementing beacons requires overcoming challenges such as device compatibility and managing large numbers of beacons. Early solutions are being developed to make sense of proximity data and apply it to use cases like understanding customer journeys and improving offline messaging.