Google Ads Offline Conversion Imports 2026: Data Manager API Guide – ALM Corp

Google is updating the process for offline conversion imports within Google Ads, requiring a transition to the Data Manager API by June 15, 2026.

Offline conversion imports allow advertisers to track actions that occur outside of a digital environment—such as a sale completed in a physical store or a lead converted via a phone call—and upload that data back into Google Ads to measure campaign performance.

The migration to the Data Manager API is intended to protect attribution and reporting for these conversions. Attribution is the technical process of assigning credit to the specific ads or keywords that led a user to eventually convert and the update aims to maintain the accuracy of this data.

According to a guide published by ALM Corp, advertisers must follow specific migration steps to move their existing workflows to the Data Manager API to ensure there is no disruption in how their conversion data is reported.

Businesses that rely on offline data to calculate the return on investment for their advertising spend will need to complete this transition before the June 15, 2026 deadline to avoid potential gaps in their attribution reporting.