Google’s Performance Max placement rules create API confusion

A discrepancy emerged between Google’s official stance on API-based placement exclusions and real-world observations, particularly for Performance Max (PMax) campaigns.

The contradiction:

• Google claims API-based placement exclusions don’t work for PMax
• Multiple advertisers report successful API-based exclusions
• UI-based exclusions function as expected

The inconsistency between Google’s stated policy and actual functionality creates uncertainty for advertisers managing campaigns programmatically.

Why we care. This discrepancy will affects how they manage placement exclusions at scale through APIs and automation tools. The confusion could impact campaign safety and brand protection strategies, especially for advertisers running Performance Max campaigns across multiple accounts.

If exclusions aren’t being implemented in an efficient manner – your ads could be showing on sites of disrepute.

Reality check. The issue was initially brought up by Navah Hopkins, Brand Evangelist of Optmyzr on LinkedIn, based off a conversation she saw on Google’s help forum. There we see a Google advisor commenting that placement exclusion isn’t supported in PMax campaigns:

However, recent testing by automation expert Nils Rooijmans confirmed on LinkedIn, that API-originated placement exclusions are indeed working for Performance Max campaigns, contradicting Google’s official position:

Another advertiser in the help forum states they are able to add exclusions through their API.

Bottom line. The documented behavior suggests Google’s official stance may need updating, as API-based exclusions appear to function similarly to UI-based ones.