Google is making an important change that could quietly break some existing advertising workflows if nobody is paying attention. Starting April 1, 2026, certain developers will no longer be able to upload Customer Match data through the Google Ads API. The restriction is aimed at developer tokens that are either new to Customer Match or have not uploaded Customer Match data during the six-month window from October 2025 through March 2026. If those tokens are not on Google's allowlist, upload attempts will fail.

