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Privileged Worker Token Exchange with Token Vault is currently in Beta. To learn more about Auth0’s product release cycle, read Product Release Stages. To participate in this program, contact Auth0 Support or your Technical Account Manager.
Token Vault supports the Privileged Worker Token Exchange, which enables a client application to exchange a signed JWT (subject token) for an external provider’s access or refresh token (requested token). After successful user authentication and authorization, a client application typically passes the user context, which contains the user’s identity, permissions, and session state, as an access or refresh token to perform the token exchange with Token Vault. In service-to-service flows, a client application, such as a backend application or service worker, may need to access resources on the user’s behalf, but because the “user is not present” in an interactive session, the client application doesn’t have access to the user context. In these service-to-service scenarios, the client application can generate a signed JWT bearer token and use it as the subject token to perform the token exchange and receive the necessary tokens to call external APIs. This means the client application can perform actions on the user’s behalf without an active user interaction or session. To use the Privileged Worker Token Exchange with Token Vault, the client application must be a highly privileged client that can also request refresh tokens from external providers via Token Vault. It should authenticate with Token Vault using asymmetric cryptographic methods such as Private Key JWT assertion or mutual TLS authentication.

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Prerequisites

Only certain types of clients can use the Privileged Worker Token Exchange with Token Vault:
  • The client must be a first-party client, i.e. the is_first_party property is true.
  • The client must be a confidential client with a valid authentication mechanism, i.e. the token_endpoint_auth_method property must not be set to none.
  • The client must be OIDC conformant, i.e. the oidc_conformant must be true.
Before configuring Privileged Worker Token Exchange for your client application:
  1. Enable the Token Vault grant type for your client application.
  2. Configure Private Key JWT or mutual TLS authentication for your client application.

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Configure client application

To configure the client application’s privileged access to Token Vault, you need to provide a public key that will be used to verify a signed JWT as the subject token.
  1. Navigate to Applications > Applications and select your application.
  2. Select the Settings tab, scroll to the Privileged Worker section, and toggle on Enable Privileged Worker. In the modal, select an existing public key credential or upload a new one, then select Save.
  3. Once the credential is saved, enter at least one IP address or CIDR range in the IP Allowlist field.
  4. Select Save Changes.
Token Vault settings showing Enable Token Vault toggle and Credential selector
Configuring an ip_allowlist is required as part of the client configuration. Any Privileged Worker token exchange request from an IP not in the list will be rejected.

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Create signed JWT subject token

After configuring your client application with the public key, you need to create the subject token that will be exchanged for an access token for an external API. The subject token is a JSON Web Token (JWT) with the necessary claims. It is signed with the private key. The JWT has a standard format and claims: Header Payload The following is an example JWT:
Do not include personally identifiable information (PII) in audit_context. This value is recorded in tenant logs and may be visible to administrators and log streaming destinations.
The following code sample is a script that generates a signed JWT subject token:

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Request token for external API

Once you have the signed JWT, you can make a request for the access token for the external API: