Ready to start sending and receiving text messages with Twilio Programmable SMS using Java?
This Programmable SMS Quickstart for Java will teach you how to do this using the Twilio Java helper library for our Communications REST API.
In this Quickstart, you will learn how to:
- Sign up for Twilio and get your first SMS-enabled Twilio phone number
- Set up your development environment to send and receive messages
- Send your first SMS
- Receive inbound text messages
- Reply to incoming messages with an SMS
Prefer to get started by watching a video? Check out our Java SMS Quickstart video on Youtube.
If you already have a Twilio account and an SMS-enabled Twilio phone number, you’re all set here! Feel free to jump to the next step.
If you don't currently own a Twilio phone number with SMS functionality, you'll need to purchase one. After navigating to the Buy a Number page, check the "SMS" box and click "Search."
You’ll then see a list of available phone numbers and their capabilities. Find a number that suits your fancy and click "Buy" to add it to your account.
Now that you have a Twilio account and a programmable phone number, you can start writing some code! To make things even easier, we'll set up our Java environment and then download Twilio's official helper library for Java applications.
Already have your Java development environment all set up, and have a Twilio Java Helper library configured in your classpath? Feel free to skip the next two sections, and get right into sending your first text message with Twilio!
To send your first SMS, you’ll need to have the Java Standard Edition (SE) Development Kit (JDK) installed - if you don't know if you have the JDK installed, run the following command to see what version you have:
You should see something similar to this output:
The Twilio SDK requires Java SE 7 or higher, which will appear as version number "
1.7" or above when you run the above command.
If you have an older version of Java or no JDK at all, you'll need to install the JDK before going any further. Follow the directions for installing the Java SE Development Kit for your platform (Windows, Mac, Linux) from the Java SE Download Page.
Got Java all set up and ready to go? Fantastic!
Next, download the standalone Twilio Java Helper Library. With that library, you'll have Java classes that help you call out to Twilio API's using Java, along with all the other dependencies you'll need to get going. We'll be using this "fat jar" file with all the dependencies in this SMS Quickstart. When you download the fat jar file, download the one with a name similar to twilio-7.x-jar-with-dependencies.jar.
Prefer to use Maven, Gradle, or another build tool? The Twilio Java Helper Library docs have information on how to install using a build automation tool.
This Twilio Java helper library is not meant for use in Android applications! Use this library for servers, command line applications, and similar projects.
If you want to send an SMS from a mobile application, you should have a server component with your Twilio credentials where your app sends an HTTP request. Shipping your Twilio Account SID and Auth Token to end users is a security risk for your Twilio account.
Now that we have the JDK setup and the Twilio Java Helper library downloaded, 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
SmsSender.java and type or paste in this code sample.
You’ll need to edit this file a little more before your message will send:
Swap the placeholder values for
AUTH_TOKEN with your personal Twilio credentials. Go to https://www.twilio.com/console and log in. On this page, you’ll find your unique Account SID and Auth Token, which you’ll need any time you send messages through the Twilio Client like this. You can reveal your auth token by clicking on the eyeball icon:
SmsSender.java and replace the values for
AUTH_TOKEN with your unique values.
Please note: it's okay to hardcode your credentials when getting started, but you should use environment variables to keep them secret before deploying to production. Check out how to set environment variables for more information.
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 so you can see the magic happen! As above, you should use E.164 formatting for this value.
Save your changes and compile this Java class from your terminal:
javac -cp twilio-7.17.6-jar-with-dependencies.jar SmsSender.java
We need to include that Twilio jar with the dependencies to compile our class from the command line. If you are using an Integrated Development Environment (IDE) such as IntelliJ IDEA, Netbeans or Eclipse, you can simply add that Twilio jar to your classpath or your project libraries like any other dependency. You can also use a build tool like Maven or Gradle to build and run your Java application - just specify Twilio's helper library as a dependency.
Once you have the Java class built, you will need to run it - if you are running it from the command line on macOS or Linux, the command will look like this:
java -cp .:twilio-7.17.6-jar-with-dependencies.jar SmsSender
On Windows, the equivalent command looks like this:
java -cp .;twilio-7.17.6-jar-with-dependencies.jar SmsSender
The difference is that on Windows, the Java classpath separator on the command line is a semicolon, and on macOS or Linux, it is a colon.
That's it! In a few moments, you should receive an SMS from your Twilio number on your phone.
Are your customers in the U.S. or Canada? You can also send them MMS messages by adding just one line of code. Check out this guide to sending MMS to see how it's done.
If you are on a Twilio Trial account, your outgoing SMS messages are limited to phone numbers that you have verified with Twilio. Phone numbers can be verified via your Twilio Console's Verified Caller IDs.
When your Twilio number receives an incoming message, Twilio will send an HTTP request to a server you control. This callback mechanism is known as a webhook. When Twilio sends your application a request, it expects a response in the TwiML XML format telling it how to respond to the message.
Let's see how we would build this in Java using the Spark web application framework. Spark is a lightweight web application framework and is completely different from the big data software named Apache Spark.
Spark requires its own library, separate from the Twilio Java helper library, which you can install using the directions on the Download Spark Java page. You'll find directions for using Spark with Maven, Gradle, or as a standalone download. Spark does not come with a logging implementation, but it does work with the Simple Logging Facade 4 Java (SLF4J), which you can also include in your Java classpath.
You can certainly set up all of your dependencies on the command line like we did when we sent the SMS through Twilio above, but it's a little easier to get everything set up using a Java integrated development environment (IDE). We are going to use the free, community edition of IntelliJ IDEA, which you can download from JetBrains. You can download JAR files and use them directly with IntelliJ IDEA, or you can use a dependency manager such as Maven or Gradle. We will use Gradle with IntelliJ IDEA to build our application.
If you haven't downloaded and installed IntelliJ IDEA Community Edition, please go ahead and do that now! After you run IDEA for the first time, you will see a screen that looks like this:
Choose 'Create New Project,' and the new New Project wizard will start:
On the left-hand side of that dialog box, choose Gradle (instead of Java), so that IntelliJ IDEA will set your project up to use Gradle for dependency management. You could also choose to use Maven here instead - the process is almost the same.
After choosing Gradle, verify that IntelliJ IDEA has a project SDK (you'll need Java 8 or higher, so version 1.8 or above), and then click Next.
On the next screen in the wizard, you will be asked for a
group id, an
artifact id, and a
version number. For the group id, you can use a reverse domain name, such as com.yourcompany.sms, and for the artifact id, you should use your project name, like sms-quickstart-app. You can leave the version as 1.0-SNAPSHOT. After filling in these fields, click Next.
On this Gradle settings screen, you can leave the defaults and then click Next.
Last, you can confirm the project name and project directory to use for your Quickstart web application. The defaults are probably fine here as well. Clicking Finish will take you to your new IntelliJ Project. If you just installed IntelliJ IDEA, the IDE will download Gradle and do some setup and installation.
Now that we've got our project all set up, we just have a few more steps! We'll need the Twilio Java helper library, and the Spark Java web application framework as dependencies, along with the logging implementation so that we can see status messages from Spark. With Gradle, we can add those to the build.gradle file that IntelliJ created for us. Go ahead and find
build.gradle in the sidebar and click on it to open it.
You'll need to add three lines to your
build.gradle file, in the dependencies group:
compile group: "com.twilio.sdk", name: "twilio", version: "7.17.+"
compile group: "com.sparkjava", name: "spark-core", version: "2.7.1"
compile group: "org.slf4j", name: "slf4j-simple", version: "1.7.21"
With these three dependencies, Gradle will download the appropriate libraries for you and add them to the classpath for building and running your Java application.
Now that we have all of that out of the way, it's time to write some code!
We'll need to start by creating a Java class in our project. In IntelliJ IDEA, select the
java folder under
main. Next, open the File menu at the top of the screen. Choose the New submenu, and then Java Class.
A small popup window will show, and you can create a new class. Name your class
SmsApp - capitalization is important because it has to match the code sample.
You should have an
SmsApp.java source code file now. Copy and paste the code from the code sample into that source code file.
This Java code will listen for inbound HTTP GET requests to '/', respond with "Hello Web," and listen to inbound HTTP POST requests for '/sms', and respond with TwiML markup for an SMS Message.
After you get your code in place, you can right-click on the SmsApp class in the project outline on the left-hand side, and then choose the Run 'SmsApp.main()' menu item.
The Java spark web application server will start listening on port 4567. You can try it out by going to http://localhost:4567/ in your web browser.
One important thing to note - if you make a change to your code, and want to run the server again, you will need to stop the currently running application with the red stop button. Only one application can use port 4567 at a time, so if you run your Java application while an older version is still running, the new application will immediately exit.
You'll need to make your application accessible over the internet. While you can do that in any number of ways, we recommend a tool that provides an externally accessible URL called ngrok. We'll show you how to set that up next so your app can receive messages.
We’ve just built a small Java web application to receive incoming messages. Before it will work, we need to make sure that Twilio can reach our application.
Most Twilio services use webhooks to communicate with your application. When Twilio receives an SMS, for example, it reaches out to a URL in your application for instructions on how to handle the message.
When you’re working on your Java web application in your development environment, your app is only reachable by other programs on your computer, so Twilio won’t be able to talk to it. We need to solve this problem by making your application accessible over the internet.
While there are a lot of ways to do this, like deploying your application to Heroku or AWS, you'll probably want a less laborious way to test your Twilio application. For a lightweight way to make your app available on the internet, we recommend a tool called ngrok. Ngrok listens on the same port that your local web server is running on and provides a unique URL on the ngrok.io domain, forwarding incoming requests to your local development environment. It works something like this:
If you haven't already, install ngrok. Make sure it's the ngrok version that’s appropriate for your operating system and take care that the '
ngrok' command is on your system path. If you're working on a Mac or Linux, you're all set. If you're on Windows, follow our guide on how to install and configure ngrok on Windows. For more info on ngrok, including some great tips and tricks, check out this in-depth blog post.
The following command would use ngrok to expose
port 4567 to the public Internet. Type the following command on the command line:
ngrok http 4567
And you will see output similar to this:
Now we have a new external URL.
For Twilio to know where to look, you need to configure your Twilio phone number to call your webhook URL whenever a new message comes in.
- Log into Twilio.com and go to the Console's Numbers page.
- Click on your SMS-enabled phone number.
- Find the Messaging section. The default “CONFIGURE WITH” is what you’ll need: "Webhooks/TwiML".
- In the “A MESSAGE COMES IN” section, select "Webhook" and paste in your URL: in this quickstart step above, it would be:
https://aaf29606.ngrok.io/sms- be sure to add '/sms' at the end.
Save your changes - you’re ready!
Make sure you are running your '
ngrok' command on the command line, and running your web application from IntelliJ IDEA. If you restarted ngrok, you will have to update your webhook in the console to use the right url.
With both of those servers running, we’re ready for the fun part - testing our new Java web application!
Send an SMS from your mobile phone to your Twilio phone number that's configured with this webhook. You should see an HTTP request with a 200 OK in your ngrok console. Your Java web application will process the text message, and you’ll get your response back as an SMS.
Now that you know the basics of sending and receiving SMS text messages with Java, you might want to check out these resources.
- Messaging API documentation
- TwiML reference docs
- Tutorials with full sample applications in Java
- 0 to 60 with Java – Sending an SMS in a Minute