Calculate the hash server-side

JS

const crypto = require("crypto");

const userId = "";
const appSecret = "";

const hash = crypto
.createHmac("sha256", appSecret)
.update(userId)
.digest("hex");

Python

import hmac
import hashlib

app_secret = b"<app_secret>"
user_id = b"<user_id>"

hash = hmac.new(app_secret, user_id, hashlib.sha256).hexdigest()

PHP

<?php

$appSecret = '<APP_SECRET>';
$userId = '<USER_ID>';
$hash = hash_hmac('sha256', $userId, $appSecret);