Version 5.x has been out of support since December 13, 2022, and this corresponding section of the documentation is no longer maintained. We strongly recommend upgrading to a supported version.


While logging is more low level “printf” style - events represent higher level information about certain operations in IdentityServer. Events are structured data and include event IDs, success/failure information, categories and details. This makes it easy to query and analyze them and extract useful information that can be used for further processing.

Events work great with structured logging stores like ELK, Seq or Splunk.

Emitting events

Events are not turned on by default - but can be globally configured in the ConfigureServices method, e.g.:

services.AddIdentityServer(options =>
    options.Events.RaiseSuccessEvents = true;
    options.Events.RaiseFailureEvents = true;
    options.Events.RaiseErrorEvents = true;

To emit an event use the IEventService from the DI container and call the RaiseAsync method, e.g.:

public async Task<IActionResult> Login(LoginInputModel model)
    if (_users.ValidateCredentials(model.Username, model.Password))
        // issue authentication cookie with subject ID and username
        var user = _users.FindByUsername(model.Username);
        await _events.RaiseAsync(new UserLoginSuccessEvent(user.Username, user.SubjectId, user.Username));
        await _events.RaiseAsync(new UserLoginFailureEvent(model.Username, "invalid credentials"));

Custom sinks

Our default event sink will simply serialize the event class to JSON and forward it to the ASP.NET Core logging system. If you want to connect to a custom event store, implement the IEventSink interface and register it with DI.

The following example uses Seq to emit events:

public class SeqEventSink : IEventSink
    private readonly Logger _log;

    public SeqEventSink()
        _log = new LoggerConfiguration()

    public Task PersistAsync(Event evt)
        if (evt.EventType == EventTypes.Success ||
            evt.EventType == EventTypes.Information)
            _log.Information("{Name} ({Id}), Details: {@details}",
            _log.Error("{Name} ({Id}), Details: {@details}",

        return Task.CompletedTask;

Add the Serilog.Sinks.Seq package to your host to make the above code work.

Built-in events

The following events are defined in IdentityServer:

  • ApiAuthenticationFailureEvent & ApiAuthenticationSuccessEvent

    Gets raised for successful/failed API authentication at the introspection endpoint.

  • ClientAuthenticationSuccessEvent & ClientAuthenticationFailureEvent

    Gets raised for successful/failed client authentication at the token endpoint.

  • TokenIssuedSuccessEvent & TokenIssuedFailureEvent

    Gets raised for successful/failed attempts to request identity tokens, access tokens, refresh tokens and authorization codes.

  • TokenIntrospectionSuccessEvent & TokenIntrospectionFailureEvent

    Gets raised for successful token introspection requests.

  • TokenRevokedSuccessEvent

    Gets raised for successful token revocation requests.

  • UserLoginSuccessEvent & UserLoginFailureEvent

    Gets raised by the quickstart UI for successful/failed user logins.

  • UserLogoutSuccessEvent

    Gets raised for successful logout requests.

  • ConsentGrantedEvent & ConsentDeniedEvent

    Gets raised in the consent UI.

  • UnhandledExceptionEvent

    Gets raised for unhandled exceptions.

  • DeviceAuthorizationFailureEvent & DeviceAuthorizationSuccessEvent

    Gets raised for successful/failed device authorization requests.

Custom events

You can create your own events and emit them via our infrastructure.

You need to derive from our base Event class which injects contextual information like activity ID, timestamp, etc. Your derived class can then add arbitrary data fields specific to the event context::

public class UserLoginFailureEvent : Event
    public UserLoginFailureEvent(string username, string error)
        : base(EventCategories.Authentication,
                "User Login Failure",
        Username = username;

    public string Username { get; set; }