Auth0 Support Center - SAML Addon Mappings from ID Token Custom Claims in Actions

SAML Addon Mappings from ID Token Custom Claims in Actions

Sep 10, 2025

Overview

When using rules, it is possible to map values from transient user object properties to the SAML response using the SAML addon. Mapping values from the user object is no longer possible with Actions.

This article explains how to achieve the same result when using Actions.

Applies To

Auth0 as SAML IDP
Mappings
SAML Addon Mappings.

Cause

Transient user object properties are not mapped to the SAML response in Actions.

Solution

To achieve the same result, instead of adding the desired values to the user object, those values have to be added to the ID token as custom claims.

For example:

Action's code:

exports.onExecutePostLogin = async (event, api) => {
api.idToken.setCustomClaim('IDTokenClaimName',"Hello!");
};

SAML Addon mappings:

{
  "mappings": {
    "IDTokenClaimName": "SAMLResponseAttrName"
  }
}

Then, the SAML response will include: