Programmable Messaging Ruby Quickstart

With just a few lines of code, your Ruby application can send and receive text messages with Twilio Programmable SMS.

This Ruby SMS Quickstart will teach you how to do this using our Communications REST API, the Twilio Ruby helper library, and Ruby’s Sinatra framework to ease development. If you prefer using Rails, check out this blog post.

In this Quickstart, you will learn how to:

1. Sign up for Twilio and get your first SMS-enabled Twilio phone number
2. Set up your development environment to send and receive messages
3. Send your first SMS
4. Receive inbound text messages
5. Reply to incoming messages with an SMS

Prefer to get started by watching a video? Check out our Ruby SMS Quickstart video on Youtube.

Sign up for Twilio and Get a Twilio Phone Number

Install the Twilio CLI

We'll need to use the Twilio CLI (command line interface) for a few tasks, so let's install that next.

Next, we need to install Ruby and the Twilio Ruby Helper Library.

Install Ruby and the Twilio Helper Library

To send your first SMS, you’ll need to have Ruby and the Twilio Ruby helper library installed.

Install Ruby

If you’re using a Mac or Linux machine, you probably already have Ruby installed. You can check this by opening up a terminal and running the following command:

$ ruby --version

You should see something like:

ruby 2.7.2

Windows users can use RubyInstaller to install Ruby.

Twilio’s Ruby SDK is tested against and supports Ruby versions from 2.4 through 3.0. (Got an older version of Ruby? You can use rbenv, RVM or Homebrew to upgrade to the minimum supported version.)

Install the Twilio Ruby Helper Library

The easiest way to install twilio-ruby is from RubyGems.

gem install twilio-ruby

Manual Installation

Or, you can clone the source code for twilio-ruby, and install the library from there.

"Permission Denied"

If the command line gives you a long error message that says Permission Denied in the middle of it, try running the above commands with sudo:

sudo gem install twilio-ruby

Send an outbound SMS with Ruby

Now that we have Ruby and twilio-ruby installed, we can send an outbound text message from the Twilio phone number we just purchased with a single API request. Create and open a new file called send_sms.rb and type or paste in this code sample.

You’ll need to edit this file a little more before your message will send.

Replace the placeholder credential values

1. Go to the Twilio Console and find your unique Account SID and Auth Token.
2. Open send_sms.rb and replace the values for account_sid and auth_token with your Account SID and Auth Token.

Replace the from phone number

Remember that SMS-enabled phone number you bought just a few minutes ago? Go ahead and replace the existing from number with that one, making sure to use E.164 formatting:

[+][country code][phone number including area code]

Replace the to phone number

Replace the to phone number with your mobile phone number. This can be any phone number that can receive text messages, but it’s a good idea to test with your own phone to see the magic happen! As above, you should use E.164 formatting for this value.Save your changes and run this script from your terminal:

ruby send_sms.rb

That's it! In a few moments, you should receive an SMS from your Twilio number on your phone.

Install Sinatra and set up your development environment

In order to receive and reply to incoming SMS messages, we'll need to create a very lightweight web application that can accept incoming requests. We'll use Sinatra for this Quickstart, but if you prefer to use Rails, you can find instructions in this blog post.

First, you need a Gemfile with the following content on it. Create a file named Gemfile and paste the following into it:

# Gemfile
source 'https://rubygems.org'

gem 'sinatra'
gem 'twilio-ruby'

Ruby projects use Bundler to manage dependencies, so the command to pull Sinatra and the Twilio SDK into our development environment is bundle install.

bundle install
...
Use `bundle show [gemname]` to see where a bundled gem is installed. 

Create a simple Sinatra application

We can test that our development environment is configured correctly by creating a simple Sinatra application. Copy the following code and drop it in a new file called quickstart.rb:

require 'sinatra'

get '/' do
  "Hello World!"
end

We can then try running our new Sinatra application with the command ruby quickstart.rb. You can then open http://localhost:4567 in your browser and you should see a "Hello World!" message.

Receive and reply to inbound SMS messages with Sinatra

When someone sends an SMS to your Twilio phone number, Twilio makes an HTTP request to your server asking for instructions on what to do next. Once you receive the request, you can tell Twilio to reply with an SMS, kick off a phone call, store details about the SMS in your database, or trigger something else entirely - it’s all up to you!

For this quickstart, we’ll have our Sinatra app reply to incoming SMS messages with a thank you to the sender. Open up quickstart.rb again and update the code to look like this code sample:

Save the file and restart your app with:

ruby quickstart.rb

Now Twilio will be able to find your application - but first, we need to tell Twilio where to look. We will use ngrok to do this.

Configure ngrok and your webhook URL

We'll use ngrok to set up a tunnel from the public internet to your localhost. This will let us use a public URL as the webhook for your application.

First, download and configure ngrok.

Next, run this command to have ngrok set up a tunnel to your localhost:

ngrok http 4567

This will start an ngrok tunnel. Copy down the Forwarding URL that ends with ngrok.io.

Then, you need to configure your Twilio phone number to call your webhook URL whenever a new message comes in:

1. Go to Phone Numbers > Active Numbers in the Twilio Console.
2. Select the SMS-enabled Twilio number you want to use.
3. For the A MESSAGE COMES IN webhook, enter the ngrok URL you copied down earlier. Append /sms-quickstart to the end of the URL.

Test your application with a text

Now that everything is glued together, it's time to test.

Send a text message from your mobile phone to your Twilio phone number. You'll see a couple of things happen very quickly:

1. Your Sinatra dev server will note a new connection
2. Twilio will forward your response back as an SMS!

Where to next?

Now that you know the basics of sending and receiving SMS text messages with Ruby and Sinatra, you might want to check out these resources.

• Dive into the API Reference documentation for Twilio SMS
• Learn how to create an SMS conversation in Ruby
• Track the delivery status of your messages with Ruby
• Send an SMS during a phone call
• Learn how to build cool things with TwilioQuest, our interactive, self-paced game that teaches you how to Twilio.

We can't wait to see what you build!