The EOS Online Subsytem (OSS) Plugin

An Overview of the Epic Online Services Plugin.

Choose your operating system:




Epic Online Services (EOS) is an engine-agnostic system that provides a range of cross-platform online features, including: player-centric features such as achievements and leaderboards, commercial features such as the ability to purchase in-game items, and social features such as voice communication and friends lists.

Unreal Engine can help you implement EOS in your project through its Online Subsystem (OSS) plugin, without the need to write code using the EOS SDK directly. The Online Subsystem plugin provides a common interface across all exposed online services in Unreal Engine. To use this feature, developers must register and configure their products with Epic Account Services (EAS), and then enable and configure a few plugins to expose EOS functionality through the OSS interface.

For more information on EAS and EOS, please see the Epic Online Services developer documentation.


To begin leveraging EOS in your project, you must first enable the EOS OSS plugins. You can find them by going to the Edit menu and selecting Plugins to open the Plugin Browser.

Within the Plugin Browser, locate and enable Online Subsystem EOS and EOS Shared. If you want to add voice chat support through EOS, enable the EOS RTC IVoiceChat plugin as well.

After enabling the plugins, you will need to configure them. Some of the following configuration steps require product-related settings or identifiers received after registering your product with EOS.

If you have not registered your product with EOS, you can register it on the Epic Developer Portal.

EOS Settings

The following settings relate to EOS' platform-specific configuration. For more detail, see the EOS API Reference page about the Platform Options data structure.

  • Cache Dir: This is the location in which EOS stores temporary data.

  • Default Artifact Name: Games shipped on the Epic Games Store and that run through the Epic Games Launcher use an artifact name to look up settings data. This field specifies a default name.

  • Tick Budget in Milliseconds: This setting establishes a per-tick time limit on EOS' operations. You can remove the limit by setting this value to zero.

  • Enable Overlay: Use this to enable or disable all overlays. Some overlays may be platform-specific, such as the e-commerce overlay which is only valid for titles shipping on the Epic Games Store.

  • Enable Social Overlay: The social overlay shows information about friends, achievements, and extra authentication steps. You can disable this overlay individually while leaving other overlays enabled. This setting has no effect if Enable Overlay is turned off.

  • Require Being Launched by Epic Games Store: For titles that ship on the Epic Games Store, activating this setting causes the game to verify ownership before launching, and requires launching through the Epic Games Launcher. If the end user attempts to launch the game using any other method, the game's process will terminate and relaunch itself through the Epic Games Launcher.

  • Artifacts: The Epic Games Store supports multiple artifacts for a single product. For example, your product can have separate internal artifacts for development, testing, and for the released version that your customers use. This array contains settings for each named artifact. There must be at least one artifact in the array, and the Default Artifact Name value must match the name of one of the array elements. See Artifact Settings for more information about these settings.

Artifact Settings

Artifact settings that you configure here should match the settings for your registered product. You can find settings for your products on the Developer Portal (requires login).

  • Artifact Name: This is the name of the artifact. For example, MyGameStaging or MyGameRelease.

  • Client ID: This ID should start with "xyz" as the first 3 characters.

  • Client Secret: This is the password that is used to verify your Client ID.

  • Product ID: The EOS SDK uses this ID to identify your product.

  • Sandbox ID: The artifact belongs to the sandbox with this ID value. Typically, the product has only a single Sandbox ID.

  • Deployment ID: Deployment IDs differ for each artifact. For example, if you have MyGameStaging and MyGameRelease artifacts, they will each have their own Deployment IDs.

  • Encryption Key: When you upload data to an EOS service, this 64-byte hexadecimal string is used to encrypt it. Unlike other settings, EOS does not manage this Encryption Key and it is not stored in your product settings. The key is unique to your game and not known to Epic Games, to protect users' data privacy.

EOS Plus Plugin Settings

EOS Plus is an experimental OSS plugin that combines the features of the EOS SDK with those of another online platform (such as Xbox Live, PlayStation, Steam, and so on) into a single, crossplay-compatible Online Subsystem.

To use this plugin, you must first register and configure your product in the Developer Portal for each platform you want to support. The platform-specific versions of EOS SDK contain detailed instructions for using the features of the platform they support.

Before using this plugin, you must configure the following settings:

  • Use Epic Account Services: When enabled, the EOS OSS plugin will use the platform-specific authentication token to sign the user into their Epic Account automatically. This requires that the user has linked their Epic Account to their account from the other platform; if they have not, the logs will report this event as an error. You can redirect the user to the account linking page to complete this process, where they can log in and complete the account linking process on their own through the Accounts tab.

  • User Cross-platform User IDs: This setting enables EOS Connect features with the platform specific authentication token.

  • Mirror Stats to EOS: If this option is enabled, EOS Plus will send a duplicate of all Stats information to the EOS OSS plugin.

  • Mirror Achievements to EOS: If this option is activated, EOS Plus will send a duplicate of all Achievement data to the EOS OSS plugin.

  • Use Crossplay Sessions: This setting is required to play cross-platform network games. It also makes the EOS Sessions Interface the primary session interface.

  • Mirror Presence to EAS: This option determines whether the EOS Plus plugin will also send Presence data to the EOS OSS plugin. Presence data is only available when using Epic Account Services.

Project Settings

Once you have set up your product on the Developer Portal and configured the plugins, there are a few settings you need to configure in the project's DefaultEngine.ini file.

Engine Settings

Follow these steps to configure your project to use the Online Subsystem EOS plugin:

  1. In the [OnlineSubsystemEOS] section, verify or add the following line to ensure that the Online Subsystem EOS is enabled:

  2. In the [OnlineSubsystem] section, verify or add the following line to ensure that EOS is your default platform:

  3. In the [/Script/Engine.GameEngine] section, verify or add the following line to ensure that the engine will use the EOS NetDriver:

  4. If you intend to use EOS' P2P socket functionality for player hosted matches, verify or add the following line to the [/Script/OnlineSubsystemEOS.NetDriverEOS] section:


Your DefaultEngine.ini file should now contain the following lines within their respective sections:





EOS Plus Settings (Optional)

If you want to configure your project to implement crossplay between EOS and another online platform, make these additional modifications:

  1. Verify that the EOS Plus plugin is enabled by looking for the following line in the [OnlineSubsystemEOSPlus] section:

  2. In the [OnlineSubsystem] section, change your default online platform from EOS to EOSPlus, and add the name of the other online platform. In this example, we will use Steam as our second platform. When you are finished, you should have these lines:

  3. The engine needs to know that EOS and EOSPlus network ID types are compatible in order to enable interaction between the platforms. Add the following lines to the [/Script/OnlineSubsystemUtils.OnlineEngineInterfaceImpl] section:


Your DefaultEngine.ini file should now contain the following lines within their respective sections. You may also need to replace Steam with a different online platform name:




The DefaultPlatformService setting in the [OnlineSubsystem] section replaces the value that you set earlier.

EOS Voice Communications

You can configure Lobby sessions to create a linked voice chat room. Users who join the lobby (including the lobby creator) will automatically join the voice chat room. To configure this, set both the FOnlineSessionSettings::bUseLobbiesIfAvailable and FOnlineSessionSettings::bUseLobbiesVoiceChatIfAvailable values to true.

Individual users can control their interaction with voice chat rooms using their IVoiceChatUser interface instances, which you can retrieve using FOnlineSubsystemEOS::GetVoiceChatUserInterface.

The IVoiceChatUser interface enables interaction with local hardware, online chat rooms, and other voice chat users. You can select input or output devices, change volume levels, block or mute specific users, and register for events such as players joining or leaving the channel, starting or stopping talking, and so on.

When using FOnlineSubsystemEOS::GetVoiceChatUserInterface, the system will handle the initializing, connecting, and log in automatically. However, depending on how you integrate IVoiceChat, you can still manually join and leave trusted server channels. Refer to the [Trusted Server Integration] section of the EOSVoiceChat plugin documentation for more information.

언리얼 엔진 문서의 미래를 함께 만들어주세요! 더 나은 서비스를 제공할 수 있도록 문서 사용에 대한 피드백을 주세요.
설문조사에 참여해 주세요