Cannot use Test Developer Token to link or create clients under Test MCC

Hi Google Ads API Team,

I’m building an integration using the REST API (v21) with a developer token approved for Test Access only.

My setup

• Account 1: account@.....

  • Has a developer token (ID: a7d3rvlyJBNO9haM1DVPnA)

  • Status: Test Access only

  • Can call customers:listAccessibleCustomers successfully

  • ⚠️ Does notshow the red “Test account” label in the UI

• Account 2: ratoblaas6@....

  • Shows the red “Test account” label in the UI

  • ⚠️ API Center is disabled: “The API Center is not available for test accounts. Use the developer token from your production manager account (not a test account).”

  • So I cannot get a developer token here.

This leaves me in a situation where:

• One account has a Dev Token but no red label.

• The other has the red label but no Dev Token.
  

I can fetch accessible accounts with the test developer token:

export async function getAccessibleCustomerId(userAccessToken: string) {
  const res = await fetch(
    " https://googleads.googleapis.com/v21/customers:listAccessibleCustomers ",
    {
      headers: {
        Authorization: `Bearer ${userAccessToken}`,
        "developer-token": process.env.GOOGLE_DEVELOPER_TOKEN!,
      },
    }
  );
  return await res.json();
}

This returns valid customer IDs (e.g. customers/1234567890).


What fails ❌

a. Sending MCC invitation ( customerClientLinks:mutate )
export async function inviteClientFromMcc(clientCustomerId: string) {
  const MCC_ID = process.env.SANDBOX_MANAGER_ID!;
  const mccAccessToken = await getMccAccessToken();

  const res = await fetch(
    ` https://googleads.googleapis.com/v21/customers/${MCC_ID}/customerClientLinks:mutate` ,
    {
      method: "POST",
      headers: {
        Authorization: `Bearer ${mccAccessToken}`,
        "developer-token": process.env.GOOGLE_DEVELOPER_TOKEN!,
        "login-customer-id": MCC_ID,
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        operation: {
          create: {
            clientCustomer: `customers/${clientCustomerId}`,
            status: "PENDING",
          },
        },
      }),
    }
  );

  return await res.json();
}

export async function inviteClientFromMcc(clientCustomerId: string) {
  const MCC_ID = process.env.SANDBOX_MANAGER_ID!;
  const mccAccessToken = await getMccAccessToken();

  const res = await fetch(
    ` https://googleads.googleapis.com/v21/customers/${MCC_ID}/customerClientLinks:mutate` ,
    {
      method: "POST",
      headers: {
        Authorization: `Bearer ${mccAccessToken}`,
        "developer-token": process.env.GOOGLE_DEVELOPER_TOKEN!,
        "login-customer-id": MCC_ID,
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        operation: {
          create: {
            clientCustomer: `customers/${clientCustomerId}`,
            status: "PENDING",
          },
        },
      }),
    }
  );

  return await res.json();
}

Response: