TL;DR: In this series, you will use modern technologies like Vue.js, AWS Lambda, Express, MongoDB, and Auth0 to create a production-ready application that acts like a micro-blog engine. The first part of the series focused on the setup of the Vue.js client and on the definition of the Express backend API.

The second part (this one) will show you how to prepare your app for showtime. You will start by signing up to AWS and to mLab (where you will deploy the production MongoDB instance), then you will focus on refactoring both your frontend and backend apps to support different environments (in this case, development and production).

Note: the instructions described in this article probably won't incur any charges. Both AWS and mLab have free tiers that support a good amount of requests and processing. If you don't extrapolate usage, you won't have to pay anything.

If interested, you can find the final code developed in this part in this GitHub repository.

"Learn how to deploy Express APIs to AWS Lambda and to deploy @vuejs apps to AWS S3 for production-ready apps."

Before Starting

Before you can start following the instructions presented in this article, you will need to make sure you have a version of the app running on your local machine. If you already followed the instructions described in the previous article and already have the app running locally, you can jump this section. Otherwise, you can opt to ignore the previous article and take the shortcut described in the following subsections.

Configure an Auth0 Application and an Auth0 API

As you want your micro-blog engine to be as secure as possible and don't want to waste time focusing on features that are not unique to your app (e.g. identity management features), you will use Auth0 to manage authentication. As such, if you haven't done so yet, you can sign up for a free Auth0 account here.

After signing up to Auth0, you can head to the APIs section of the management dashboard and click on the Create API button. In the form that Auth0 shows, you can fill the fields as follows:

  • Name: "Micro-Blog API"
  • Identifier: https://micro-blog-app
  • Signing Algorithm: RS256

To finish the creation of your Auth0 API, click on the Create button. After that, head to the Applications section and click on the Create Application button. In the form presented, fill the options as follows:

  1. The name of your application: you can enter something like "Vue.js Micro-Blog".
  2. The type of your application: here you will have to choose Single Page Web Applications.

After clicking on the Create button, Auth0 will redirect you to a new page where you will need to tweak your application configuration. For now, you are only interested in adding values to two fields:

  • "Allowed Callback URLs": Here you will need to add http://localhost:8080/callback so that Auth0 knows it can redirect users to this URL after the authentication process.
  • "Allowed Logout URLs": The same idea but for the logout process. So, add http://localhost:8080/ in this field.

After inserting these values, hit the Save Changes button at the bottom of the page and leave the page open (you will need to copy some properties from it soon).

Creating a MongoDB Instance Locally

After creating both the Auth0 Application and the Auth0 API, you will need to initialise a MongoDB instance to persist your users' data. To facilitate this process, you can rely on Docker (for this, you will need Docker installed in your machine). After installing it, you can trigger a new MongoDB instance with the following command:

docker run --name mongo \
    -p 27017:27017 \
    -d mongo

Yup, that's it. It's easy like that to initialise a new MongoDB instance in a Docker container. For more information about it, you can check the instructions on the official Docker image for MongoDB.

Forking and Cloning the App's GitHub Repository

With both Auth0 and a MongoDB instance properly configured, the next thing to do is to fork and clone the GitHub repository created throughout the previous article. After forking it into your own GitHub account, you can use the following commands to clone your fork locally:

# replace this with your own GitHub user

# clone your fork
git clone$GITHUB_USER/vue-js-lambda-part-1.git

After that, you can install the backend and frontend dependencies:

# move into the Vue.js app
cd vue-js-lambda-part-1/client

# install frontend dependencies
npm i

# then move into the Express app
cd ../backend

# install backend dependencies
npm i

Then, you will need to open the project root (the parent of the client and backend directories) into your preferred IDE and proceed as follows:

  1. On the ./client/src/AuthService.js file, replace the domain, clientID, and audience properties of the object passed to auth0.WebAuth with the properties from the Auth0 Application and API created previously (audience is the identifier of you Auth0 API).
  2. On the ./backend/src/routes.js file, replace all appearances of with your own Auth0 domain and replace the clientId property of the object passed to auth0.AuthenticationClient with the Client ID of your Auth0 Application.

After changing these files, you can use the following commands to start your application:

# from the backend directory, start the Express app in the background
node src/index.js &

# then move into the client directory
cd ../client

# and run the Vue.js app
npm start

Now, if you open http://localhost:8080 on a web browser, you should be able to sign in into your app through Auth0 and to post messages to your micro-blog engine.

Running locally your Vue.js and Express app

AWS Lambda Overview

As AWS Lambda is one of the most popular serverless solutions available, it probably doesn't need a thorough introduction. Nevertheless, even though you are going to use Claudia.js to abstract the usage of the AWS Lambda service, a basic understanding about how this solution works might come in handy.

On its own, AWS Lambda functions are not enough to handle HTTP requests originating from the Internet (and from your users' browsers when accessing the Vue.js application). If you were creating your serverless functions without the help of Claudia.js, you would have to use the AWS API Gateway solution along with Lambda. This would be needed because Lambda functions are raw functionalities that can be triggered by different clients (for example, from other resources at your AWS account, which wouldn't need the API Gateway).

As such, to make Lambda functions available to public clients (like your Vue.js app), you would need to set up an API Gateway that would integrate both ends (Lambda and Vue.js, for example).

This (extremely) short introduction about AWS Lambda and AWS API Gateway is not even close to provide a complete explanation on how these features can be used (nor it is the goal here). If you need more explanation around these topics, you can refer to the official documentation available at AWS and, if you are wondering how cumbersome would be to remove Claudia.js from your setup, you can refer to this nice blog post that shows how to use the AWS CLI to create everything manually.

Signing Up to AWS

Now, to set up AWS Lambda functions and an API Gateway (both manually or with the help of Claudia.js), you will need an AWS account. If you don't have one yet, you can open this page to create your account. As you can see there, new AWS accounts include 12 months of free tier access which, as described here, grant you (among other things):

  • Amazon API Gateway: 1 million API calls per month;
  • AWS Lambda: 1 million free requests per month;

This will probably be enough for the use case presented here. Unless you end up creating the next Twitter. :)

Deploying a MongoDB Instance on the Cloud

After signing up to AWS, the next service that you will need to sign up to is mLab. You will need this service because it facilitates the deployment of production-ready, world-wide available MongoDB instances.

Note: you can also choose to host a MongoDB instance on your own servers (like on an EC2 instance). However, to keep things easier to grasp, this article won't cover the steps needed to do so.

After signing up to mLab, you can head to their dashboard and click on the Create New button. Then, you will have to choose a cloud provider (as you will use this instance with AWS Lambda functions, it might make sense to choose Amazon Web Services here) and a Plan Type. For the last option, sandbox (the free plan) will be more than enough.

Now, you can click on Continue and choose a region for your deployment. Choose some region geographically close to yourself. Then, when you click on Continue again, mLab will require you to choose a database name. Here, you can set something like micro-blog and click on Continue one more time. After this, mLab will present the details of your instance where, if everything is looking good, you will be able to finish the process by clicking on the Submit Order button.

The last thing you will need to do to use your MongoDB instance is to define a user and password for your connections. So, click on your instance and choose the Users tab. There, you can click on the Add Database User button and fill the form with the details of your new user (e.g. micro-blog-db-user as the username and 963-DbP4ssas the password).

That's it, you are now ready to start refactoring your project source code to deploy it to production. Just leave this page open for further reference (you will need to copy the connection string from here).

Preparing the Express App for Claudia.js

Having both your AWS and mLab accounts properly created, you can start changing your code. In the subsections presented here, you will install some dependencies, refactor parts of your Express API, and deploy your API to AWS Lambda.

Installing Claudia.js

The process of installing and configuring Claudia.js can be pretty simple. Basically, to prepare your environment and your project to integrate with Cluadia.js, you will need to:

  1. Install Claudia.js globally (you will need its CLI in a moment). This can be done by issuing npm install claudia -g in any terminal.
  2. Install Claudia.js as a project development dependency on the backend subproject. You can achieve this by issuing npm install claudia -D on a terminal pointing to the backend directory.
  3. Create an AWS profile and configure it locally so Claudia.js can deploy the project for you.

To create an AWS profile, go to the Users section of your IAM Management Console and click on add user. Then, you can configure your new user as follows:

  • User name: Just enter something meaningful like claudiajs-manager.
  • Access type: Check only the programmatic access option as you won't use this user to log into the AWS console.

After that, click on the next (permissions) button and click on the create group button. You will need a new group to restrict access to what the Claudia.js user needs (i.e. the policy types). So, on the page that creates groups, configure the new one as follows:

  • For the Group name, input something meaningful like lambda-group.
  • Then, check the AWSLambdaFullAccess, AmazonAPIGatewayAdministrator, and the IAMFullAccess policy types to grant Claudia.js enough access.

Now you can hit the create group button which will redirect you back to the user creation page. There, you will need to make sure that only your new group (e.g. lambda-group) is selected. Having checked that, click on Next: Review.

On the next step, as shown in the next screenshot, you will see a page where you will have access to both the access and the secret access keys. Leave this page open so you can copy both keys.

AWS access key and secret access key strings.

The last things you will need to do is to head back to the terminal, move into your home directory (~/), and update the .aws/credentials file to include both keys (you might actually need to create the .aws directory and the credentials file inside it):

aws_access_key_id = AKIR...WDNA
aws_secret_access_key = kuNgBlgz...xsBl

Just make sure you replace AKIR...WDNA and kuNgBlgz...xsBl with your own credentials and that you replace auth0 with a meaningful profile name.

In case you need more info about this topic, you can check the official Claudia.js docs or you can get in touch in the comments section down below.

Refactoring your Index Express File

To use your Express API with AWS Lambda, Claudia.js requires that you export an express instance (instead of triggering listen manually) from the ./backend/src/index.js file. So, open this file and replace the app.listen call (the last three lines of this file) with this:

// ... require statements and app definition

module.exports = app;

After that, you will lose the ability to run your server locally. To circumvent this problem, you will need to create a new file called development-server.js inside the ./backend/src/ directory and add the following code to it:

const app = require('./index');

app.listen(8081, () => {
  console.log('listening on port 8081');

With that in place, you can issue node src/development-server.js from the backend directory to start the Express app in your machine.

Creating a new Auth0 Tenant for Production

As you don't want to mix development users with real users (that is, users of the production version of your app), you will need to create a new Auth0 tenant for production. Therefore, open the Auth0 dashboard in your browser and click on your picture in the upper-right corner. There, you will find an option called Create Tenant. Click on this option, enter a new tenant subdomain (e.g. micro-blog-prod), and click on the Create button.

Creating a new Auth0 tenant

After that, Auth0 will redirect you to your new tenant.

Creating a new Auth0 API

As you now have a tenant for your production environment, you will need to recreate your Auth0 API. So, go to the APIs section and click on the Create API button. For the name and the identifier of your API, you can enter the same values entered before:

  • Name: Enter something meaningful like "Micro-Blog API".
  • Identifier: Enter something meaningful like https://micro-blog-app.

Then click on the Create button and leave the management dashboard open.

Extracting Environment Variables

After creating the new Auth0 settings, you will need to replace the content of the ./backend/src/routes.js file with this:

const express = require('express');
const MongoClient = require('mongodb').MongoClient;
const auth0 = require('auth0');
const jwt = require('express-jwt');
const jwksRsa = require('jwks-rsa');

const router = express.Router();

const { AUTH0_CLIENT_ID, AUTH0_DOMAIN, MONGODB_URL } = process.env;

// retrieve latest micro-posts
router.get('/', async (req, res) => {
  const collection = await loadMicroPostsCollection();
    await collection.find({}).toArray()

const checkJwt = jwt({
  secret: jwksRsa.expressJwtSecret({
    cache: true,
    rateLimit: true,
    jwksRequestsPerMinute: 5,
    jwksUri: `https://${AUTH0_DOMAIN}/.well-known/jwks.json`

  // Validate the audience and the issuer.
  audience: 'https://micro-blog-app',
  issuer: `https://${AUTH0_DOMAIN}/`,
  algorithms: ['RS256']

// insert a new micro-post'/', checkJwt, async (req, res) => {
  const collection = await loadMicroPostsCollection();

  const token = req.headers.authorization
    .replace('bearer ', '')
    .replace('Bearer ', '');

  const authClient = new auth0.AuthenticationClient({
    domain: AUTH0_DOMAIN,
    clientId: AUTH0_CLIENT_ID,

  authClient.getProfile(token, async (err, userInfo) => {
    if (err) {
      return res.status(500).send(err);

    await collection.insertOne({
      text: req.body.text,
      createdAt: new Date(),
      author: {
        sub: userInfo.sub,
        picture: userInfo.picture,


async function loadMicroPostsCollection() {
  const client = await MongoClient.connect(MONGODB_URL);
  return client.db('micro-blog').collection('micro-posts');

module.exports = router;

If you take a close look to this file, you will notice that its new version makes your code more configurable by extracting some hard-coded values into AUTH0_CLIENT_ID, AUTH0_DOMAIN, and MONGODB_URL. From now on, these values will come from environment variables (i.e. from the process.env object). As such, before executing the Express API locally again, you will have to set these three environment variables in your machine:

export AUTH0_CLIENT_ID=KsX...mBGPy
export MONGODB_URL=mongodb://localhost:27017/

node ./backend/src/development-server.js

Don't forget: The values presented above are for illustration only, use your own values. Mainly for the AUTH0_CLIENT_ID and AUTH0_DOMAIN variables.

Wrapping your Express API with an AWS Lambda Proxy

After refactoring your Express API, you will use the claudia CLI tool to prepare a serverless proxy around it:

# make sure you are on the backend directory
cd backend

# generate the proxy
claudia generate-serverless-express-proxy --express-module src/index

Running the code above will result in the creation of a file called lambda.js. This file will act as the connection point between your Express API and the AWS Lambda infrastructure. As such, you should commit this file to your Git repository (you are committing stuff to Git, right?).

Deploying your Express App to AWS Lambda

Now, on the most expected part of this section, the deployment of your Express API to AWS Lambda, you will have to define the AWS_PROFILE that Claudia.js will use. Then, you will have to define the AUTH0_CLIENT_ID, AUTH0_DOMAIN, and MONGODB_URL variables with the settings for the production deployment (i.e. use the Auth0 properties of the new tenant you created for production and the URL provided by mLab) so you can call create on its CLI:

# define the profile Claudia.js will use
export AWS_PROFILE=auth0
export MONGODB_URL=mongodb://

# make Claudia.js create the AWS Lambda function for you
claudia create \
  --handler lambda.handler \
  --deploy-proxy-api \
  --region us-east-1 \

Note: Replace the value set to AWS_PROFILE with the name of the profile you added to ~/.aws/credentials before. Also, replace AUTH0_CLIENT_ID, AUTH0_DOMAIN, and MONGODB_URL with your production settings. Besides that, you can choose an AWS region other than us-east-1 to deploy your Lambda function.

This will result in a response like this:

saving configuration
  "lambda": {
    "role": "backend-executor",
    "name": "backend",
    "region": "us-east-1"
  "api": {
    "id": "7kq5w1ilz2",
    "url": ""

Here, you can grab the url of your new Lambda function.

If you are wondering what happened behind the scenes, the last step in the code snippet above ended up:

  • creating a role called backend-executor that has the log-writer policy attached to it (needed so your Lambda functions can write logs to CloudWatch);
  • creating a Lambda function called backend with your Express API code;
  • and creating an API Gateway (also called backend) that does nothing else besides proxying requests to your Lambda function;

And that's it. You now have deployed your Express API to AWS Lambda with the help of Claudia.js. To test it, you can issue an HTTP GET request to it like so:


Not hard, right?

Just make sure you replace in the URL with the endpoint created by Claudia.js (you can find this info in the url property of the api object returned after invoking claudia create).

"Using Claudia.js to deploy Express APIs to AWS Lambda is super easy!"

Preparing your Vue.js App to AWS S3

As you will see, the process of preparing your frontend app for AWS S3 will be easier than preparing the backend to AWS Lambda. Here, you will start by creating the production Auth0 Application. Then, you will extract some hard-coded values into environment variables. After that, you will create an AWS S3 bucket where you will deploy the Vue.js app.

Creating a new Auth0 Application

Besides recreating the Auth0 API for production, you will also need a new Auth0 Application. So, go to the Applications section of the Auth0 dashboard and click on Create Application. On the form shown, enter a meaningful name for your application (e.g. "Micro-Blog Engine") and choose the Single Page Web Applications type for it.

Then, after clicking on the Create button, open the Settings section of your new Auth0 Application and leave this page open. You will copy the Domain and Client ID properties from there soon.

Extracting Environment Variables

There are only 5 variables that you need to extract from your source code:

  • the url constant that refers to the backend API (for production this will be your AWS Lambda URL);
  • and the domain, clientID, returnTo, and redirectUri variables related to your Auth0 configuration.

To start this extraction, open the ./config/dev.env.js file of the client project and add these variables to the object passed to merge:

'use strict'
const merge = require('webpack-merge')
const prodEnv = require('./prod.env')

const APP_URL = 'http://localhost:8080/'

module.exports = merge(prodEnv, {
  NODE_ENV: '"development"',
  BACKEND_URL: '"http://localhost:8081/micro-posts/"',
  AUTH0_CLIENT_ID: '"KsX...BGPy"',
  AUTH0_DOMAIN: '""',
  AUTH0_CALLBACK_URL: `"${APP_URL}callback"`

Note: you will have to replace the values passed to AUTH0_CLIENT_ID and AUTH0_DOMAIN in the code snippet above.

Then, you will need to do a similar update but now on the ./config/prod.env.js file:

'use strict'
const APP_URL = ''

module.exports = {
  NODE_ENV: '"production"',
  BACKEND_URL: '""',
  AUTH0_CLIENT_ID: '"Pf1...lJm"',
  AUTH0_DOMAIN: '""',
  AUTH0_CALLBACK_URL: `"${APP_URL}callback"`

Note: Replace the values entered for AUTH0_CLIENT_ID, AUTH0_DOMAIN, and BACKEND_URL with the values available in your production Auth0 Application. Also, don't mind about the empty APP_URL constant in the last snippet, you will change it in a while.

With both config files (prod and dev) properly updated, you will need to update two files: AuthService.js and MicroPostsService.js. To start, you can open the ./client/src/MicroPostsService.js file and replace the url constant definition with this:

// ... import statements ...

const url = process.env.BACKEND_URL

// ... MicroPostsService class definition and export statement ...

After that, open the ./client/src/AuthService.js file and replace the constructor with this:

import auth0 from 'auth0-js'

class Auth {
  constructor () {
    this.auth0 = new auth0.WebAuth({
      // the following three lines MUST be updated
      domain: process.env.AUTH0_DOMAIN,
      clientID: process.env.AUTH0_CLIENT_ID,
      audience: 'https://micro-blog-app',
      redirectUri: process.env.AUTH0_CALLBACK_URL,
      responseType: 'token id_token',
      scope: 'openid profile'

    this.getAccessToken = this.getAccessToken.bind(this)
    this.getProfile = this.getProfile.bind(this)
    this.handleAuthentication = this.handleAuthentication.bind(this)
    this.isAuthenticated = this.isAuthenticated.bind(this)
    this.signIn = this.signIn.bind(this)
    this.signOut = this.signOut.bind(this)

  getAccessToken, getProfile, handleAuthentication, isAuthenticated, signIn, signOut ...

const auth0Client = new Auth()

export default auth0Client

As you may have noticed, the changes made to these two files refer to replacing hard-coded variables for environment variables (i.e. variables accessed through the process.env object).

Now, if you try to execute both your backend and your Vue.js apps locally, things should run smoothly:

# make sure you move to the backend subproject directory
cd backend

# then execute your backend development server in the background
node src/development-server &

# now move back to the client directory
cd ../client

# and execute your Vue.js app
npm start

Creating an AWS S3 Bucket

After preparing the Vue.js app to be deployed to production, you will have to go to the S3 section of your AWS management console. Once there, you can create on the create bucket button and fill the form presented as follows:

  • Bucket name: Enter some meaningful, DNS-compliant name like vuejs-micro-blog.
  • Region: Choose some region geographically near to you.

Then, you can click on the next button three times: one for the name and region section, one for the set properties section, and one for the set permissions section. You can leave these two sections (properties and permissions) with the default values.

On the last section, AWS will ask you to confirm the details of your new bucket. There, you can click on the create bucket button and then click on your new bucket from the list of buckets presented by the dashboard.

Now, if you open the Properties tab, you will see a new feature called Static Website Hosting. Click on this feature and check the Use this bucket to host a website option. Also, enter index.html in the Index document field and copy the URL presented in the Endpoint label. Use this URL to fill the empty constant that you left in your ./config/prod.env.js file:

'use strict'
const APP_URL = ''

// ... module.exports ...

Don't forget to add the trailing slash to the APP_URL constant.

After that, you can click save, head back to the Overview tab of your bucket, and leave this page open.

Uploading your Vue.js App to AWS S3

To upload your Vue.js app to this new AWS S3 bucket, open the client directory on a terminal and build the project for production:

# make sure you are on the client directory
cd client

# build the app for production
npm run build

This will generate a new directory called dist with all the code you need to run in production. So, back in the page you left open in the AWS console (the Overview section of your S3 bucket), you can click on upload and drag and drop the index.html file and the static directory that are available in the dist directory.

Then, you will have to click on Next and, on the set permissions section, you will have to choose the Grant public read access to this object(s) option for the Manage public permissions field. After that, you can click next twice so you reach the Review section. On this last section, click on upload and wait until AWS finishes uploading your files.

Vue.js files uploaded to AWS S3.

Now, if you open the URL created for your AWS S3 bucket on a browser, you will see your Vue.js app up, running, and consuming your AWS Lambda function.

Vue.js app running on an AWS S3 bucket.

Then, to wrap up, you will need to update the Allowed Callback URLs and the Allowed Logout URLs fields of your production Auth0 Application to support your new URL. That is, if the URL of your AWS S3 bucket is, you will have to:

  • Insert in the Allowed Callback URLs field;
  • Insert in the Allowed Logout URLs field.

After that, you will have finished deploying both your Vue.js app to AWS S3 and your Express API to an AWS Lambda function. Congratulations!

"Deploying @vuejs apps to AWS S3 is really simple."

Conclusion and Next Steps

In this part of the series, you learned about how Claudia.js can help you deploy Express APIs as AWS Lambda functions. You also learned how to extract environment variables from both your backend and client subprojects to make them ready for production. And, in the end, you created an AWS S3 bucket with static website hosting capabilities so you could upload your Vue.js app to it.

With this, you have a production-ready application built with Vue.js and Express that is deployed to AWS Lambda and to AWS S3.

For a next opportunity, you will learn how to automate the deployment process of these apps to make your development lifecycle faster. Stay tuned!