Assigning custom user IDs

This feature allows you to change the default SuperTokens user ID (UUID v4) to a value that you prefer. There are two primary use cases for this:

Use case 1: During migration of users
Use case 2: If you prefer a different user ID format than the default one.

The way this feature works is that SuperTokens will store and manage the user ID mapping in the SuperTokens core. So when that users logs in, you will get back the mapped (the custom) user ID instead of the SuperTokens user ID.

Features like user roles, user metadata, session will also all work based on the custom user ID.

Use case 1: Migration of users#

This topic is better covered under the migration section. The main purpose of this is that you can retain the existing user IDs of your users when migrating them to SuperTokens. This makes it easier to migrate users without having to update the user IDs in your database.

Use case 2: If you prefer a different user ID format than the default one.#

You can call the user ID mapping function post sign up as shown below. It is important to know that user ID mapping can only be done, before there is any other data (session, roles etc) associated with the user.

NodeJS
GoLang
Python
Other Frameworks

import SuperTokens from "supertokens-node";
import EmailPassword from "supertokens-node/recipe/emailpassword";
import Session from "supertokens-node/recipe/session";
import { RecipeUserId } from "supertokens-node";

SuperTokens.init({
    appInfo: {
        apiDomain: "...",
        appName: "...",
        websiteDomain: "..."
    },
    supertokens: {
        connectionURI: "...",
    },
    recipeList: [
        EmailPassword.init({
            override: {
                functions: (originalImplementation) => {
                    return {
                        ...originalImplementation,

                        // override the email password sign up function
                        signUp: async function (input) {
                            let response = await originalImplementation.signUp(input);

                            if (response.status === "OK" && response.user.loginMethods.length === 1 && input.session === undefined) {
                                let externalUserId = "<CUSTOM USER ID>"
                                await SuperTokens.createUserIdMapping({ superTokensUserId: response.user.id, externalUserId })
                                
                                // we modify the response object to have the custom user ID.
                                response.user.id = externalUserId
                                response.user.loginMethods[0].recipeUserId = new RecipeUserId(externalUserId);
                            }

                            return response;
                        },
                    }
                }
            }
        }),
        Session.init({ /* ... */ })
    ]
});

import (
    "github.com/supertokens/supertokens-golang/recipe/emailpassword"
    "github.com/supertokens/supertokens-golang/recipe/emailpassword/epmodels"
    "github.com/supertokens/supertokens-golang/supertokens"
)

func main() {

    supertokens.Init(supertokens.TypeInput{
        RecipeList: []supertokens.Recipe{
            emailpassword.Init(&epmodels.TypeInput{
                Override: &epmodels.OverrideStruct{
                    Functions: func(originalImplementation epmodels.RecipeInterface) epmodels.RecipeInterface {
                        // create a copy of the originalImplementation
                        originaSignUp := *originalImplementation.SignUp

                        // override the email password sign up function
                        (*originalImplementation.SignUp) = func(email, password string, tenantId string, userContext supertokens.UserContext) (epmodels.SignUpResponse, error) {

                            resp, err := originaSignUp(email, password, tenantId, userContext)
                            if err != nil {
                                return epmodels.SignUpResponse{}, err
                            }

                            if resp.OK != nil {
                                externalUserId := "<CUSTOM USER ID>"
                                _, err := supertokens.CreateUserIdMapping(resp.OK.User.ID, externalUserId, nil, nil)
                                if err != nil {
                                    return epmodels.SignUpResponse{}, err
                                }
                                resp.OK.User.ID = externalUserId
                            }

                            return resp, err
                        }

                        return originalImplementation
                    },
                },
            }),
        },
    })
}

from supertokens_python import init, InputAppInfo
from supertokens_python.asyncio import create_user_id_mapping
from supertokens_python.recipe import emailpassword, session
from supertokens_python.recipe.emailpassword.interfaces import RecipeInterface, SignUpOkResult
from typing import Dict, Any


def override_emailpassword_functions(original_implementation: RecipeInterface) -> RecipeInterface:
    original_sign_up = original_implementation.sign_up

    async def sign_up(
        email: str,
        password: str,
        tenant_id: str,
        user_context: Dict[str, Any]
    ):
        result = await original_sign_up(email, password, tenant_id, user_context)

        if isinstance(result, SignUpOkResult):
            external_user_id = "<CUSTOM USER ID>"
            await create_user_id_mapping(result.user.user_id, external_user_id)
            result.user.user_id = external_user_id

        return result

    original_implementation.sign_up = sign_up

    return original_implementation


init(
    app_info=InputAppInfo(
        api_domain="...", app_name="...", website_domain="..."),
    framework='...',  
    recipe_list=[
        emailpassword.init(
            override=emailpassword.InputOverrideConfig(
                functions=override_emailpassword_functions
            ),
        ),
        session.init(),
    ]
)

Auth Methods

Add ons

Assigning custom user IDs

Use case 1: Migration of users#

Use case 2: If you prefer a different user ID format than the default one.#

Important