EOS accounts and login

Choose EOS Auth or Connect and sign in with explicit credentials.

For a shared login flow across providers, use Sign in players. Use the EOS APIs below when your game needs direct control of EOS authentication.

You need	Login path	Identity
Epic friends, presence, or social overlay	Epic Account / Auth	Epic Account ID; game services use the associated Product User ID
EOS game services without requiring an Epic account	Connect	Product User ID (PUID)

These IDs are different. A PUID is not an Epic Account ID, Steam ID, or crossplay player handle.

Complete EOS setup. For an interactive first login, choose Account Portal. Create EosAccount (EIK Account Id) for the example’s saved account handle.

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Game module dependencies: EIKCore, BetideCore, Engine.

#include "Engine/GameInstance.h"
#include "Interfaces/IEIKOnlineServices.h"
#include "Interfaces/IEIKAuth.h"

DEFINE_LOG_CATEGORY_STATIC(LogGameEosLogin, Log, All);

void LoginEpicAccount(UGameInstance &GameInstance)
{
    const auto Services = FEIKOnlineServicesFactory::Get(GameInstance.GetWorld());
    if (!Services)
        return;
    const auto Auth = Services->GetAuthInterface();
    if (!Auth)
        return;
    Auth->Login(0, FEIKLoginCredentials::AccountPortalLogin(),
                FEIKAsyncCallback<FEIKLoginResult>::CreateWeakLambda(
                    &GameInstance, [](const TEIKAsyncResult<FEIKLoginResult> &Result) {
                        if (!Result.IsSuccess())
                        {
                            UE_LOG(LogGameEosLogin, Warning, TEXT("%s"),
                                   *Result.Error.GetLogString());
                            return;
                        }
                        UE_LOG(LogGameEosLogin, Log, TEXT("EOS account ready: %s"),
                               *Result.Result.GetValue().AccountId.ToString());
                    }));
}

Try Persistent Auth for returning players; fall back to Account Portal if no usable saved authorization exists. C++ uses FEIKLoginCredentials::PersistentAuthLogin(). Developer Tool login is for development; launcher exchange codes must come from the current launch.

Acquire the credential from its provider first. Login with EIK Connect Interface requires an explicit token for every external method; an empty token does not trigger Steam, Google, Apple, or Discord login.

Connect with a Google ID token

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Connect with a device identity

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Using the same headers and dependencies:

bool LoginEosConnect(UGameInstance &GameInstance, EEIK_EExternalCredentialType CredentialType,
                     const FString &Token, const FString &DisplayName,
                     const FEIKAsyncCallback<FEIKLoginResult> &Completion)
{
    if (Token.IsEmpty())
        return false;
    const auto Services = FEIKOnlineServicesFactory::Get(GameInstance.GetWorld());
    if (!Services)
        return false;
    const auto Auth = Services->GetAuthInterface();
    if (!Auth)
        return false;
    Auth->LoginConnect(
        0, FEIKLoginCredentials::ExternalPlatformLogin(CredentialType, Token, DisplayName),
        Completion);
    return true;
}

Use EIK_ECT_GOOGLE_ID_TOKEN with the ID token from Google for the first example. Bind Completion with CreateWeakLambda; the return value only means dispatched. After success, read the Product User ID with UEIKAuthLibrary::GetProductUserId(&GameInstance) (Auth/EIKAuthLibrary.h, module EIKBlueprints).

bool LoginEosDevice(UGameInstance &GameInstance, const FString &DisplayName,
                    const FEIKAsyncCallback<FEIKLoginResult> &Completion)
{
    if (DisplayName.IsEmpty())
        return false;
    const auto Services = FEIKOnlineServicesFactory::Get(GameInstance.GetWorld());
    const auto Auth = Services ? Services->GetAuthInterface() : nullptr;
    if (!Auth)
        return false;
    Auth->LoginConnect(0, FEIKLoginCredentials::DeviceIdLogin(DisplayName), Completion);
    return true;
}

Choose the credential type that matches the token. Google ID tokens are Connect-only in EOS; a Google server authorization code is not an ID token. Apple supplies an identity token, and Discord supplies an access token. Never log credentials.

Device ID is the token-free Connect path and needs a display name. Treat it as a device-local starting identity; offer account linking before players depend on access from another device.

Sign out

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bool LogoutEos(UGameInstance &GameInstance, const FEIKAsyncCallbackVoid &Completion)
{
    const auto Services = FEIKOnlineServicesFactory::Get(GameInstance.GetWorld());
    if (!Services)
        return false;
    const auto Auth = Services->GetAuthInterface();
    if (!Auth)
        return false;
    Auth->Logout(0, Completion);
    return true;
}

Leave active multiplayer and voice flows before signing out. In a game using UCIK identity, use Logout From Crossplay so the unified identity state is cleared too.

Linking accounts and avoiding duplicate progress

Use the Crossplay identity flow when players choose between an existing account and a new identity. Do not create another Product User ID as a generic recovery action when the player already has progress.

For direct C++ integration, IEIKAuth::LinkExternalAccount(LocalUserIndex, FEIKConnectCredentials, Completion) links an external credential to the logged-in user. Supply a fresh provider token. An account already associated with another PUID needs an explicit account-resolution flow; linking is not an automatic merge of saved progress.

Diagnose a failed login

Check the result’s error message and code, then the active sandbox/deployment, client policy, token type, and token expiry. Epic social features require an Epic-account login; a successful Connect-only login cannot supply them. Do not start a manual login while configured auto-login is still running.

Use UEIKAuthLibrary from Auth/EIKAuthLibrary.h (EIKBlueprints) for IsLoggedIn, GetEpicAccountId, and GetProductUserId. Resolve services with the current world in C++; a global service lookup can select the wrong PIE player.

EOS accounts and login

Sign in with an Epic account

Sign in with a platform token

Sign out