Hi,
Thank you for contacting the Ad Manager API support team.
You can create a test network in the Ad Manager API. To create a test network, call NetworkService.makeTestNetwork method. A MakeTestNetwork example is included in each of the client libraries . You can create only one test network for your Google account. You can check this guide for complete information. Let us know if you have any further queries.

[2025-10-06 16:44:30Z GMT] This message is in relation to case "ref:!00D1U01174p.!500Ht01u8MF3:ref" (ADR-00334704)