This disclosure relates to electronically linking offline user activity to online activity of that user. Linking offline to online activity provides real-time feedback on traffic flow from a machine-readable label (“MRL”) scan to a conversion event on a target website. Linking offline to online activity enables tracking of specific MRLs and conversion events associated therewith. Linking offline to online activity enables calculating benchmarks such as time to conversion event and best performing conversion locations for an MRL. Linking offline to online activity enhances security and data quality as each conversion event can be traced back to a unique MRL scan and a timestamp and geolocation associated with the unique MRL scan.