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 Passwordless from "supertokens-node/recipe/passwordless";
import Session from "supertokens-node/recipe/session";
import { RecipeUserId } from "supertokens-node";

SuperTokens.init({
    appInfo: {
        apiDomain: "...",
        appName: "...",
        websiteDomain: "..."
    },
    recipeList: [
        Passwordless.init({
            contactMethod: "EMAIL", // This example will work with any contactMethod
            flowType: "USER_INPUT_CODE_AND_MAGIC_LINK", // This example will work with any flowType
            override: {
                functions: (originalImplementation) => {
                    return {
                        ...originalImplementation,
                        consumeCode: async (input) => {
                            
                            // First we call the original implementation of consumeCode.
                            let response = await originalImplementation.consumeCode(input);

                            // Post sign up response, we check if it was successful
                            if (response.status === "OK") {
                                let { id, emails, phoneNumbers } = response.user;

                                if (response.createdNewRecipeUser && 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);
                                    response.recipeUserId = new RecipeUserId(externalUserId);
                                }
                            }
                            return response;
                        }
                    }
                }
            }
        }),
        Session.init({ /* ... */ })
    ]
});

import (
    "github.com/supertokens/supertokens-golang/recipe/passwordless"
    "github.com/supertokens/supertokens-golang/recipe/passwordless/plessmodels"
    "github.com/supertokens/supertokens-golang/supertokens"
)

func main() {

    supertokens.Init(supertokens.TypeInput{
        RecipeList: []supertokens.Recipe{
            passwordless.Init(plessmodels.TypeInput{
                Override: &plessmodels.OverrideStruct{
                    Functions: func(originalImplementation plessmodels.RecipeInterface) plessmodels.RecipeInterface {
                        // create a copy of the original function
                        originalConsumeCode := *originalImplementation.ConsumeCode

                        // override the sign in up function
                        (*originalImplementation.ConsumeCode) = func(userInput *plessmodels.UserInputCodeWithDeviceID, linkCode *string, preAuthSessionID string, tenantId string, userContext supertokens.UserContext) (plessmodels.ConsumeCodeResponse, error) {

                            // First we call the original implementation of ConsumeCode.
                            response, err := originalConsumeCode(userInput, linkCode, preAuthSessionID, tenantId, userContext)
                            if err != nil {
                                return plessmodels.ConsumeCodeResponse{}, err
                            }

                            if response.OK != nil {
                                if response.OK.CreatedNewUser {
                                    externalUserId := "<CUSTOM USER ID>"
                                    _, err := supertokens.CreateUserIdMapping(response.OK.User.ID, externalUserId, nil, nil)
                                    if err != nil {
                                        return plessmodels.ConsumeCodeResponse{}, err
                                    }
                                    response.OK.User.ID = externalUserId
                                }

                            }
                            return response, nil
                        }

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

from supertokens_python import init, InputAppInfo
from supertokens_python.asyncio import create_user_id_mapping
from supertokens_python.recipe import session, passwordless
from supertokens_python.recipe.passwordless.interfaces import RecipeInterface, ConsumeCodeOkResult
from typing import Dict, Any, Union

def override_passwordless_functions(original_implementation: RecipeInterface) -> RecipeInterface:
    original_consume_code = original_implementation.consume_code
    
    async def consume_code(
        pre_auth_session_id: str,
        user_input_code: Union[str, None],
        device_id: Union[str, None],
        link_code: Union[str, None],
        tenant_id: str,
        user_context: Dict[str, Any]
    ):
        # First we call the original implementation of consume_code.
        result = await original_consume_code(pre_auth_session_id, user_input_code, device_id, link_code, tenant_id, user_context)

        # Post sign up response, we check if it was successful
        if isinstance(result, ConsumeCodeOkResult):
            id = result.user.user_id
            phone_number = result.user.phone_number
            email = result.user.email
            print(id)
            print(phone_number)
            print(email)
            
            if result.created_new_user:
                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.consume_code = consume_code

    return original_implementation

init(
    app_info=InputAppInfo(api_domain="...", app_name="...", website_domain="..."),
    framework='...', 
    recipe_list=[
        passwordless.init(
            contact_config=passwordless.ContactConfig(
                contact_method="EMAIL", # This example will work with any contactMethod
            ),
            flow_type="USER_INPUT_CODE_AND_MAGIC_LINK", # This example will work with any flowType
            override=passwordless.InputOverrideConfig(
                functions=override_passwordless_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