How to Turn On API Access in Google Ad Manager (and Why MCM Partners Need It)

API access is a single switch in Google Ad Manager, but it is one of the conditions that most often delays MCM onboarding. Holuron lists it as a requirement and says accounts are delinked if its service cannot reach them through the API. Here is how to turn it on correctly.

What the Ad Manager API does

The API lets software talk to your Ad Manager network directly. Google lists uses such as managing inventory, creating orders, pulling reports and automating workflows. For an MCM partner, it is the backbone of daily work: reporting across many networks, applying pricing changes and monitoring delivery without clicking through every screen by hand.

Who can turn it on

Only a user with the Administrator role can enable API access, as Google's API access instructions explain. If you do not see the option, check your role first.

Step-by-step

1. Sign in to Google Ad Manager.
2. Go to Admin, then Global settings, then Network settings.
3. Under General settings, switch API access on.
4. Read and accept the API terms and conditions by clicking Confirm.
5. Click Save.

Google points out that API access stays inactive until you click Save. Skipping that last step is the most common reason a partner reports "no API access" after a publisher believes it is enabled.

Service accounts

Some integrations connect through a Google Cloud service account rather than a person's login. Ad Manager supports adding a service account as a user for API access. Your partner will tell you whether that applies and which email to add.

Why it must stay on

Holuron's onboarding terms say that a delink will happen if its service cannot access the account by API. Common causes of lost access include:

• someone switching API access off during a settings cleanup
• removing or deactivating the partner's users
• changing roles so the partner user loses the permissions it needs

Add a note to your internal runbook so nobody on your team changes these settings without checking first.

Quick checklist

• An Administrator is available on your team.
• API access is on and saved.
• Partner users are active.
• Your team knows not to remove them.

With the switch on and saved, one of the most common blockers is gone. Your network may be ready for the next step: get your account reviewed.