Configure Back-Channel Logout

Check the OIDC standard /.well-known/* metadata endpoint to determine if the service is available for your application. This is a read-only public endpoint.

GET https://acme.eu.auth0.com/.well-known/openid-configuration

HTTP 200
{ ..., "backchannel_logout_supported": true, 
  "backchannel_logout_session_supported": true }

Callback URLs are called on publicly-exposed endpoints and must adhere to certain restrictions:

1. You must use the HTTPS protocol. Unencrypted HTTP or any other protocols are not allowed.

2. You must not use Auth0 subdomains. Some Auth0 subdomains are:

   • auth0.com

   • auth0app.com

   • webtask.io

   • webtask.run

3. We do not recommend using IP addresses without domains. IP addresses must be public IPs to use back-channel logout. IP addresses from internal, reserved, or loopback ranges are not permitted.

Register your application to receive back-channel logout events in Auth0 Dashboard or Management API.

Auth0 DashboardManagement API

Subscribe applications

1. Navigate to Auth0 Dashboard > Applications.

2. Choose the application you want to register.

3. Select the Settings tab.

4. Under the OpenID Connect Back-Channel Logout > Back-Channel Logout URI, add the application logout URI that will receive the logout_tokens

5. Once complete, select Save Changes.

   

Unsubscribe applications

Unsubscribing your application stops the service from tracking new logins and sending logout events. The service discards pending logout events once your application is unsubscribed.

To unsubscribe your application, delete the back-channel logout URL.

1. Navigate to Auth0 Dashboard > Applications.

2. Choose the application you want to register.

3. Select the Settings tab.

4. Under the OpenID Connect Back-Channel Logout > Back-Channel Logout URI

5. Remove the back-channel URL.

6. Once complete, select Save Changes.

   

For auditing purposes, the service always logs subscribing or unsubscribing back-channel logout URLs as API Operation Event in Auth0 tenant logs. To learn more, read Logs.

Once you have configured back-channel logout via the Auth0 Dashboard or Management API, configure your application to use the service based on the technology or framework.

1. Implement end-user authentication according to your application type. 

   1. End-users should be able to log in to the application, and a session should be created. 

   2. An ID token should be issued from Auth0 and should be accessible in the application backend for further processing.

2. Extend the login process to save the sid and, optionally, sub claims after the ID token is validated. 

   1. These claims must be saved against the current application session. 

   2. The session management functions should be able to retrieve a specific session by the sid value.

3. Configure the logout callback endpoint:

   1. The endpoint must process only HTTP POST requests.

   2. Extract the logout_token parameter and validate it as a regular JWT according to the spec.

   3. Verify that the token contains an events claim with a JSON object value and a member named http://schemas.openid.net/event/backchannel-logout.

   4. Verify that the token contains the sid and/or sub claims.

   5. Verify that the token does NOT contain the nonce claim. This is required to prevent abuse by distinguishing the logout token from the ID token.

   6. Once the token is validated, retrieve the session corresponding to the received sid and/or sub value and terminate it. The exact application session termination process depends on the implementation details. For example, this event may need to be communicated to the front-end.

Coded token payload:

POST /backchannel-logout HTTP/1.1
Host: rp.example.org
Content-Type: application/x-www-form-urlencoded

logout_token=eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCIsImtpZCI6InpuTkxvOWZvdXFfVDBSQVg0YnoxeiJ9.eyJpc3MiOiJodHRwczovL2Rldi11ZG8tYXV0aDAuc3VzLmF1dGgwLmNvbS8iLCJzdWIiOiJnb29nbGUtb2F1dGgyfDExMzgxMjk4OTQ2MTg3ODc1MjMxMSIsImF1ZCI6IjQ1RFhtdE5FZVVkTXF6NHRwVkF2WVBsUUVibk1kWmxFIiwiaWF0IjoxNjYzOTMxNDQwLCJqdGkiOiI5NTFkZTVhMy1iZGM3LTQyMTAtYTM0Yy04ZWYyNDk1ZjU5ZTAiLCJldmVudHMiOnsiaHR0cDovL3NjaGVtYXMub3BlbmlkLm5ldC9ldmVudC9iYWNrY2hhbm5lbC1sb2dvdXQiOnt9fSwidHJhY2VfaWQiOiI3NGYyZDVjYjliNzFkMGQ5Iiwic2lkIjoieE52RFluUzZ0emNQNlpVbjl3alBmWTFJaGZDSWFtZ1kifQ.qXLDGHlIglXB-9v-O6fOHj3Y_sB7aIGUjZE0pap4XStPmlzNWIYbaxitBoaZmfS1IrtPubvcu1yOwyxFAjOzKFzU9H_DdLNQ0at7Xx3TEtgyPKVJt5l9wz_pGEpXdLkHHkDsPE-I3RYQzxnuNqfAzFrRHtIxKJL3Sc3VUTldaoWEtYWtfKNOd09bUyJ6mxt9S2kDjrGf6Su3OVi8RerYNlACYX4jzYV1p0oQH5wWzjCoegaFj1ilFRb8AIpTjvOfYrT44pDcLwez-V3FWy9toMnRe8jUcaZ6X0DCbOkzjzMOEKzO93yc2YzYBEktECpVJ6BCEXiPg6DFyxRfqhhyfQ

Decoded token payload:

{
  "iss": "https://dev-udo-auth0.sus.auth0.com/",
  "sub": "google-oauth2|113812989461878752311",
  "aud": "45DXmtNEeUdMqz4tpVAvYPlQEbnMdZlE",
  "iat": 1663931440,
  "jti": "951de5a3-bdc7-4210-a34c-8ef2495f59e0",
  "events": {
    "http://schemas.openid.net/event/backchannel-logout": {}
  },
  "trace_id": "74f2d5cb9b71d0d9",
  "sid": "xNvDYnS6tzcP6ZUn9wjPfY1IhfCIamgY"
}

• HTTP 200:  Confirms user logout from the specific application.

• HTTP 400: Indicates an incorrect request. The request is not understood or the token failed validation. Auth0 records the problem in tenant logs but does not attempt further requests for this specific session.

If your application did not trigger logout and received a 400 error:

1. Make sure your application has a logout callback URL registered in Auth0 Dashboard.

2. Ensure the logout callback URL is reachable from the Auth0 tenant.

3. Ensure a valid session is established. The end-user must log in to your specific application via Auth0.

   Applications receive logout events only if end-users log in to that specific app with Auth0.  If the end-user logs in to other applications, logout events do not trigger.

4. Check Auth0 tenant logs for messages about unsuccessful logout message delivery. Failed deliveries are not retried.

   

5. Make sure the logout is triggered via the standard logout endpoint. Other events do not trigger the logout events.

6. If possible, check for blocked requests on the web server and/or application firewall logs.

If the transaction still fails with a 400 error:

1. Check if the token is a standard base64-encoded JWT. Some web servers may truncate long parameters. To learn more, read Signing Algorithms.

2. If possible, capture a token and verify that it’s a JWT. Use a verified source, like JWT.IO.

3. Make sure the verification function fetches the tenant signing key dynamically via JSON Web Key Sets (JWKS).

   We do not recommend hardcoding a static key. If your configuration requires the static key to be hardcoded, ensure the configuration contains the latest public key from the Auth0 tenant.