It's 2019 and you need to receive a fax. What do you do? You could buy a fax machine, hook it up to a phone line and hand out your number. But it's 2019 not 1979, we're living in the future, so let's grab Node.js, pick a couple of APIs and turn that fax into an email instead.

You're going to need a Twilio account, a SendGrid account and this noise to remind you what you're missing out on as you build your very own fax-to-email converter.

Receiving a fax

Rather than bulky machinery we're going to use a Twilio number to receive our incoming faxes. You're going to need a Twilio number that supports fax to build this app, so log in to your Twilio account. You can buy a new number or you may already have one, just look for this icon to show that it can ...

We talk a lot about sending SMS messages from web applications, but what about sending SMS messages from a React application? There's a bit more to it than just the server-side version, but it won't take us long.

Why shouldn't I use the REST API from the client-side?

Technically you could send an SMS using the Twilio REST API directly from a JavaScript client-side application. But (and it's a very big "but") if you were to do that, you would expose your Twilio credentials to anyone using your site. A malicious user could then take those credentials and abuse them, running up a huge bill with your account.

Live view of a hacker with your account credentials

To avoid this we will create a back end application that implements the Twilio REST API, wraps up your credentials and sends SMS messages for you. Then you can call your back end ...

Create React App is a great tool for getting a React application up and running. It's a little less clear when you're building or prototyping an application that requires a server side component, like generating access tokens for Twilio Video or Chat, though. I've found it easiest to work with a server within the same project so that you can start everything up with one command.

By the end of this post you will learn how to set up an Express server that runs alongside a React app. If you can't wait then you can jump straight into the starter project on GitHub.

How it works

There is an option that you can set in Create React App's package.json that proxies non text/html requests through to an alternative back end. You can use this feature to proxy to applications running elsewhere, but today we want to be ...

The Web Audio API is a powerful browser API for creating, manipulating and analysing audio. I'm no musician, so I'll leave the creating and manipulating to the experts. Instead, in this post we're going look at analysing audio. To make things extra interesting, we're going to see how to visualise the audio in a React component with <canvas>.

When we're done we'll have a React application that can listen to the microphone on your computer and show a waveform to visualise the data.

Getting started

We'll need Node.js to run the application, so make sure you have it installed. I've started the application for us, so follow these instructions to get it running:

1. Clone or download the repo from GitHub

1. Change into the directory and install the dependencies with npm

1. Start the application

Sharing music over playlists is a great way to discover new and old music. Spotify has collaborative playlists, but I don't like how they let your friends re-order and delete songs from the list. We can fix this by building our own collaborative playlist that only allows additions using the Spotify Web API. With the Twilio API for WhatsApp we can let our friends send in a song whenever they are struck by inspiration.

In this post we are going to build a WhatsApp bot that can do all of the above using Ruby on Rails.

Getting started

To build this application we will need a few things:

• Ruby version 2.5.1 installed
• Rails and bundler, which can be installed with gem install rails bundler
• A Twilio account (sign up for a free Twilio account here)
• The WhatsApp sandbox set up in our Twilio account
• A Spotify developer account ...

I 💖 emojis, so when I heard about the new Twilio API for WhatsApp I wanted to build something emojiriffic. Inspired by Monica Dinculescu’s to_emoji Twitter bot and emoji translator I decided to build a WhatsApp text-to-emoji translator. You can try it out now by sending your message to our WhatsApp number +441745472072.

Here’s how you too can build this app.

🛠 Tools

I decided to build this project using Node.js, following in the footsteps of Monica’s projects. WhatsApp messages via Twilio result in webhooks, much the same as receiving an SMS message to a Twilio number, so if you’ve built a Twilio SMS application before this will be familiar. For ease of deploying this, I’m going to build this as a Twilio Function.

If you want to follow along with building the emoji translator you’ll need:

• A Twilio account (sign up for a free ...

We’ve looked at how to choose cameras in JavaScript using the mediaDevices API, particularly for the case of mobile devices with a front and back camera, and now it’s time to put that into practice in an application. In this post we will use what we learned to build a camera switcher into a video chat application using Twilio Video.

Getting started

We’re going to build this off a slightly modified version of the Twilio Video quickstart application. In order to build this app you will need:

• Node.js (I’m using the current latest version; 10, but it works with older versions)
• ngrok so that you can visit your development application from your mobile device
• A Twilio account; you’ll need your account SID, available on your Twilio dashboard, and an API key and secret, which you can generate in your console

Clone the repo for ...

We’ve looked before at how to capture a user’s screen in Chrome and Firefox. Good news, another browser has support now, Microsoft’s Edge.

Let’s see how we can capture the screen with Edge.

What you need

• The latest version of Edge, which is currently version 42 with EdgeHTML version 17 (if you’re on a Mac like me, you can get a free virtual machine with Windows 10 and Edge installed to test on)
• A text editor
• A local web server – I like to use serve for things like this
• Either ngrok or an equivalent tunnelling service or TLS certificates set up for localhost (we’ll see why later)

Screen Capture

Whereas Chrome required an extension to be built and Firefox used getUserMedia with a mediaSource constraint of "screen" to get a handle on the stream of the screen, once again Edge uses a different method ...

Most smart phones come with a front and back camera, when you’re building a video application for mobile you may want to choose or switch between them.

If you’re building a chat app you probably want the front camera, but if you’re building a camera app then you’re more interested in the rear camera. In this post we’re going to see how to choose or switch between cameras using the mediaDevices API and media constraints.

What you’ll need

To follow along with this post you’ll need:

• An iOS or Android device with two cameras to test with, if you have two webcams this will work on your laptop too
• ngrok so you can easily access the project from your mobile device (and because I think ngrok is awesome)
• The code from this GitHub repo to get you started

To get the code, clone ...