Auth0 on Phoenix - Basic Configuration

Today I’m documenting the process of setting up Auth0 and webpack2 on a newly created Phoenix project

creating the project

Create the project by running the generator

Mix MyApp

Do not use –no-brunch. We’ll remove that manually.

Webpack Setup

I’m basing the webpack on an earlier publication by Matthew Lehner. His writeup is excellent but I noticed a few breaking changes trying to get webpack2 to work.

The first step is to remove the brunch configuration.

rm brunch-config.js

Next we install Webpack2 as well as our presets.

npm install --save-dev webpack babel-core babel-loader 
npm install --save-dev babel-preset-es2015 babel-preset-es2016

optionally, you can include

npm install --save-dev babel-preset-es2017
npm install --save-dev babel-preset-react

Next, create webpack.config.js at the top level of your application.

let path = require('path');

module.exports = {
  entry: {
    app: path.join(__dirname, "web/static/js/app.js")
  output: {
    path: path.join(__dirname, "priv/static/js"),
    filename: "[name].js"
  resolve: {
    modules: [ "node_modules", __dirname + "/web/static/js" ]
  module: {
    loaders: [{
      test: /\.js$/,
      exclude: /node_modules/,
      loader: "babel-loader",
      query: {
        //add presets as necessary.
        presets: ["es2015", "es2016"] 


With that, You want to then add a watch script to npm. I also reccomend adding an «engines» property to lock down our node version.

It should look something like this.

  "repository": {},
  "license": "MIT",
  "scripts": {
    "watch": "webpack --watch-stdin --progress --color"
  "engines": {
    "npm": "6.9.x"
  "dependencies": {
    "phoenix": "file:../../deps/phoenix",
    "phoenix_html": "file:../../deps/phoenix_html"
  "devDependencies": {
    "babel-core": "^6.23.1",
    "babel-loader": "^6.3.0",
    "babel-preset-es2015": "^6.22.0",
    "babel-preset-es2016": "^6.22.0",
    "babel-preset-es2017": "^6.22.0",
    "babel-preset-react": "^6.23.0",
    "webpack": "^2.2.1"

Next we want to remove the brunch watcher and add a webpack command to config/dev.exs

config :web, MyApp,
  http: [port: 4000],
  debug_errors: true,
  code_reloader: true,
  check_origin: false,
  watchers: [
    npm: ["run", "watch", cd: Path.expand("../", __DIR__)]    

The cd: Path.expand(«../», DIR) ensures that our watcher will be run from the path of the root of our application. This will be very important if we run our phoenix app in an umbrella project.

Auth0 Setup

Auth0 is an authentication as a service platform for secure login and user management. I’m using it for all but a few future projects because its secure, supports multitenancy and multifactor login as well as built in social integration to google, facebook, twitter, linkedin and github without me having to put in any extra effort.

In This post, I’m going to cover a login through auth0’s server. In a future post, I’ll cover doing an auth0 oauth trhough our application server allowing us to setup sessions through guardian. For now, I will demonstrate how to just get the jwt token.

auth0-lock is the js file that contains their login widget. It can be installed via npm.

npm install --save auth0-lock

Now in your app.js add in the following code

import 'phoenix_html'
import socket from "./socket"

import Auth0Lock from 'auth0-lock';
let credentials = {
  domain: $YOUR_AUTH0_DOMAIN,
  clientId: $YOUR_CLIENT_ID

const cid = credentials.clientId;
const domain = credentials.domain;

const lock = new Auth0Lock(cid, domain);;

lock.on("authenticated", function(authResult) {
  lock.getProfile(authResult.idToken, function(error, profile) {
    if (error) {
      // Handle error
    localStorage.setItem('id_token', authResult.idToken);
    // Display user information
    console.log('your jwt token is', authResult.idToken)

Run mix phoenix.server and you should now see auth0 load up when you visit localhost:4000 in your browser.