Hey there, I’ve run into this exact confusion before! Let me break it down clearly:

Google Cloud does NOT currently offer a public API for creating or adding payment methods to billing accounts. This is a common pain point because while the Billing Accounts API lets you create accounts easily, payment method operations are locked down for security and compliance reasons—handling sensitive financial data requires strict controls that Google hasn’t opened up to general API access yet.

Here’s what you need to know:

• Right now, adding or managing payment methods can only be done manually through the Google Cloud Console web interface. There’s no way to automate this via public APIs, even if you created the billing account using the billingAccounts API.
• If you’re looking to scale billing account management, a workaround is to set up a master billing account with your preferred payment method first in the console, then use the API to create sub-billing accounts and link them to the master account. Sub-accounts will inherit the master’s payment method, which avoids needing to add payment details to each new account individually.
• For enterprise-level bulk management needs, you could reach out to the Google Cloud sales team to inquire about custom solutions or restricted API access—but this is only available to specific customers meeting certain business criteria.

内容的提问来源于stack exchange，提问作者Farhan Munir