OAuth-based App Flip Linking (App Flip) allows your users to easily and quickly link their accounts in your authentication system to their Google accounts. If your app is installed on your user’s phone when they initiate the account linking process, they are seamlessly flipped to your app to obtain user authorization.
This approach provides a faster and easier linking process since the user does not have to re-enter their username and password to authenticate; instead, App Flip leverages the credentials from the user's account on your app. Once a user has linked their Google account with your app, they can take advantage of any integrations that you have developed.
You can set up App Flip for both iOS and Android apps.

Requirements
To implement App Flip, you must fulfill the following requirements:
- You must have an Android or iOS app.
- You must own, manage and maintain an OAuth 2.0 server which supports the OAuth 2.0 authorization code flow.
Design guidelines
This section describes the design requirements and recommendations for the App Flip account linking consent screen. After Google calls your app, your app displays the consent screen to the user.
Requirements
- You must communicate that the user’s account is being linked to Google, not to a specific Google product, such as Google Home or Google Assistant.
Recommendations
We recommend that you do the following:
Display Google's Privacy Policy. Include a link to Google’s Privacy Policy on the consent screen.
Data to be shared. Use clear and concise language to tell the user what data of theirs Google requires and why.
Clear call-to-action. State a clear call-to-action on your consent screen, such as “Agree and link.” This is because users need to understand what data they're required to share with Google to link their accounts.
Ability to cancel. Provide a way for users to go back or cancel, if they choose not to link.
Ability to unlink. Offer a mechanism for users to unlink, such as a URL to their account settings on your platform. Alternatively, you can include a link to Google Account where users can manage their linked account.
Ability to change user account. Suggest a method for users to switch their account(s). This is especially beneficial if users tend to have multiple accounts.
- If a user must close the consent screen to switch accounts, send a recoverable error to Google so the user can sign in to the desired account with OAuth linking and the implicit flow.
Include your logo. Display your company logo on the consent screen. Use your style guidelines to place your logo. If you wish to also display Google's logo, see Logos and trademarks.

在原生應用程式中實作 App Flip
如要實作 App Flip,您必須修改應用程式中的使用者授權碼,以便接受 Google 提供的深層連結。
如要在 Android 應用程式中支援 App Flip,請按照 Android 實作指南中的指示操作。
如要在 iOS 應用程式中支援 App Flip,請按照 iOS 實作指南中的說明操作。
測試應用程式快速連結
在提供經過驗證的正式版應用程式和正常運作的 OAuth 2.0 伺服器之前,系統可能會使用範例和測試應用程式來模擬 App Flip。
在 App Flip 期間,Google 應用程式會先開啟您的應用程式,然後向 OAuth 2.0 伺服器要求授權碼回應,在最後一個步驟中,系統會將回應傳回 Google 應用程式。
必要條件
如要模擬 Google 應用程式並觸發啟動應用程式的意圖,請下載並安裝 Android 和 iOS 適用的 App Flip Test Tool。
下載並安裝適用於 Android 和 iOS 的 App Flip 範例,以模擬應用程式並選取 OAuth 2.0 回應類型。
測試序列
- 開啟應用程式翻轉測試工具。
- 按下
Try Flip!
即可啟動 App Flip 範例應用程式。 - 從「Sample」應用程式中的圓形按鈕選取回應。
- 按下
Send
即可將模擬的 OAuth 2.0 回應傳回至測試工具。 - 請查看測試工具記錄訊息,找出 auth_code 或錯誤詳細資料。
正式版測試
完成註冊程序和 OAuth 2.0 伺服器實作後,您可以在實際工作環境中測試 App Flip。
建議使用單一 Google 帳戶和工作專屬電子郵件地址進行自動化測試。
以 Google 帳戶持有人身分登入後,您可以使用「已連結的帳戶」查看帳戶連結狀態。您也可以在這裡取消連結帳戶,以便重複測試。
您也可以選擇導入 RISC,透過程式碼取消連結,並通知 Google 這項變更。