In short: Since December 2025 the Bing Ads API accepts Google sign-in. The new grants GoogleOAuthDesktopMobileAuthCodeGrant and GoogleOAuthWebAuthCodeGrant authenticate Microsoft Advertising with the same Google identity you already use for Google Ads. A March 2026 fix preserved the refresh token. It's onboarding friction removed, not a new capability. One auth model across both platforms, less code to maintain.
Twelve years of working with the Google Ads API taught me a boring truth. The code that talks to the platform is the easy part. The maintenance hours go into the code that keeps two sets of credentials alive. Since December 2025, half of that problem is gone, because the Bing Ads API now accepts Google sign-in.
The new grants are called GoogleOAuthDesktopMobileAuthCodeGrant and GoogleOAuthWebAuthCodeGrant. They let you authenticate the Microsoft Advertising API with the same Google identity you already use for Google Ads. An early version had a gap that dropped the Google refresh token, but a March 2026 fix closed it.
Why it matters
Cross-platform tooling has always paid an auth tax. Two identity providers, two token lifecycles, two piles of credential code doing the same job. Folding Microsoft into Google OAuth gives you one mental model for both platforms and meaningfully less code in any tool that touches them. ALM Corp’s walkthrough covers the onboarding flow in detail.
This is onboarding friction removed, not a new capability. But for agencies and multi-account scripts, less auth plumbing is exactly the kind of change that quietly makes everything else easier to build.
How to use it
If you’re building or refactoring a multi-platform connector, unify the auth layer under one Google OAuth flow instead of maintaining a separate Microsoft credential path. Pick the grant that matches your runtime. GoogleOAuthWebAuthCodeGrant fits a server-side app with a redirect URI, GoogleOAuthDesktopMobileAuthCodeGrant fits installed tooling. Store and refresh the Google token exactly as you already do for Google Ads. Thanks to the March 2026 fix the refresh token survives, so you’re not re-prompting users on every session.
It pairs naturally with the year’s other convergence wins. Richer Google import, AI Max parity, New Customer Acquisition import from Google PMax. One identity, two platforms, less code between them.
One catch is worth flagging. A shared identity is also a shared point of failure. Treat the Google token’s storage and rotation with the same care you’d give a Microsoft credential. Convenience at the auth layer only counts as a win when the security posture comes with it.
For the full sweep of where the Microsoft Advertising API caught up to Google this year, read the Microsoft API year in review. Then go delete one credential path from your codebase. Few refactors feel this good.
