In order to provide the best experience to players for Google Play Games on PC,
[we require that your Google Play Games on PC and mobile (Android) versions of
your game](https://developer.android.com/games/playgames/identity) provide a seamless cross-device
experience using our new [Google Play Games Services v2](https://developer.android.com/games/pgs/overview) SDK
to be considered [optimized for
Google Play Games on PC](https://developer.android.com/games/playgames/checklist#optimized-requirements).

Here's a summary of the requirements:

- Players on mobile (Android) and Google Play Games on PC (on PC) are [automatically signed in to Google Play Games Services](https://developer.android.com/games/pgs/signin) within your game when possible, and their non-tutorial progress is linked to their Google Play Games Services Player ID. On other devices, the game automatically restores this progress when there are no conflicts with the local state.
  - Please note that the user may be automatically signed into your game with Google Play Games Services, but not sign in with your existing identity system (e.g. guest accounts). In these cases, given the user is logged in with Google Play Games Services and has the expectation that their progress is being saved, you still must backup and restore the user's progress. **The only exception is when the user specifically understands that the guest mode is tied to a single device.**
  - [Google Play Games Services v2 Sign-in](https://developer.android.com/games/pgs/signin) must be used to satisfy this requirement. If you are currently using v1 Sign-in, we have guidance for migrating [Java](https://developer.android.com/games/pgs/android/migrate-to-v2) and [Unity](https://developer.android.com/games/pgs/unity/unity-start) integrations.
- If your game has other Identity solutions , link the Google Play Games Services Player id to these solutions so that players don't have to restore their credentials manually when using a new device.
- When there are conflicts on progress (a player signs in with Google Play Games Services and another identity platform), you should resolve it in a way your players can expect and understand. This could be asking the player which account they want to play with, preferring the local progress, or merging the progress.

We acknowledge that your existing Identity solutions have their own complexities, and we are flexible on edge cases that arise from identity collisions and resolution. In the end, the requirement is that players will automatically have their progress or state restored when switching between Android (including phones and tablets) and Google Play Games on PC.

We recommend taking a look [at this page](https://developer.android.com/games/playgames/integrating-pgs-existing-id-solutions) for recommendations on how you could integrate Google Play Games Services with your existing identity system. For example, some games may choose to make a 1:1 connection between Google Play Games Services and their existing identity system (or as we refer to it in the page linked above, a **binding** solution). Other games may choose to associate a Google Play Games Services account with a number of user-associated accounts to restore state (or as we refer to it in the page linked above, a **recall** solution).

You can use the test cases [on this page](https://developer.android.com/games/playgames/continuity-expected-behaviors) to evaluate your own solution against the requirements.
| **Note:** We strongly recommend enabling [next generation IDs](https://developer.android.com/games/pgs/next-gen-player-ids) as you configure your PGS project. This will [eventually become the default for
| all PGS projects](https://android-developers.googleblog.com/2023/02/enable-next-generation-ids-for-better-play-games-services-support-for-all-google-accounts.html), and enables better support for all accounts, including [those under supervision](https://support.google.com/families/answer/9499456).

Here's a checklist of our required and encouraged behaviors related to Google Play Games Services sign in on Google Play Games on PC.

| **ID** | **Importance** | **Description** |
|---|---|---|
| 1.1 | Required | Sign players in with [Google Play Games Services v2 Sign-in](https://developer.android.com/games/pgs/signin) on Android devices and Google Play Games on PC. <br /> Integrate the new [Google Play Games Services v2 SDK](https://developer.android.com/games/pgs/overview) with your Android and Google Play Games on PC builds, and enable the [Sign-in functionality](https://developer.android.com/games/pgs/signin) within your game. Use the credentials from signed in players to power requirement 1.2. <br /> Note that v1 Sign-in does not meet the requirement. If you use Google Play Games Services v1 currently in your game, you need to upgrade to [v2](https://developer.android.com/games/pgs/signin). For more information about migrating your integration, see the [Java](https://developer.android.com/games/pgs/android/migrate-to-v2) and [Unity](https://developer.android.com/games/pgs/unity/unity-start) guides. |
| 1.2 | Required | Back up and restore player progress by the Play Games Services Player ID. <br /> This is not required when the user understands that the progress is tied to the local device and would be lost when going to another device or the progress is just within the tutorial. <br /> To ensure players do not lose their progress when switching or resetting devices, or if they play on multiple devices, ensure their progress is backed up to a cloud save solution, and use the Play Games Services Player ID as a key, [securely](https://developer.android.com/games/pgs/signin#secure-access) if using your own backend game server. When players sign in with Play Games Services, check whether progress exists for that account and if it does, allow the player to pick up where they left off. You can use your own cloud save solution or Play Games Services [Saved Games](https://developer.android.com/games/pgs/savedgames) <br /> If the player is not signed in with Play Games Services, try to maintain the player's progress locally, then sync that progress when the player eventually signs in to Play Games Services. This helps to prevent losing any of the player's progress if the player postpones signing in to your game. |
| 1.3 | Best Practice | Provide a sign-in button for signed-out players. <br /> Players may opt out of using Play Games Services and therefore not automatically sign in to your game. By providing a sign-in button for signed out players, you allow players to change their mind and sign-in to Play Games Services as they get more invested in your game. <br /> The sign-in button should be easy for players to find; for example, it should be accessible from your main screen or located in the Settings screen. This button should not be buried multiple levels deep in your game menu. |
| 1.4 | Good-to-have | Follow Google branding guidelines. <br /> To provide players with an end-to-end experience that is attractive and consistent, implement the [Play Games Services branding guidelines](https://developer.android.com/games/pgs/branding). |