Integrating Twilio with Nitric

What we'll be doing

In this guide we'll use the Nitric Framework with Twilio to build a serverless API that can send SMS to users. This won't include a frontend, however you can look at how to integrate a Nitric API in one of our other comprehensive guides.

Getting Started

Create a Project

Create a new project using:

nitric new
? What is the name of the project? nitric-twilio
? Choose a template: official/TypeScript - Starter
? Glob for the function handlers? functions/*.ts

This will scaffold the project ready for defining your API.

Create a Twilio Account

To integrate with Twilio, it's important to create a Twilio account. If you don't already have an account, there's an option to start a free trial here. This trial doesn't ask for any payment details and provides a decent amount of free credits.

Once you've gone through the account creation and verification, you'll arrive at the dashboard. There is a section which contains the important API credentials. These are used to connect to the API so keep them in mind.

Create the Messenger Class

The messenger class acts as a helper wrapper for sending text messages. It accepts the account SID and the auth token and creates a client. This client is then used in the single method send which accepts a text message object and creates it.

// common/messenger.ts

import twilio, { Twilio } from 'twilio';

class Messenger {
  private client: Twilio;

  constructor(twilioAccountSID: string, twilioAuthToken: string) {
    this.client = twilio(twilioAccountSID, twilioAuthToken);
  }

  async send(text): Promise<string> {
    try {
      const message = await this.client.messages.create(text);
      return `${message.dateCreated}: Successfully sent text message`;
    } catch (err) {
      return `An error occured: ${err}`;
    }
  }
}

export default Messenger;

You will need to add the twilio module using your preferred package manager.

npm install twilio

Create the API

For the API we will have a single POST route send. This done by creating an API resource using the Nitric SDK and defining a new route.

// functions/text.ts

import { api } from '@nitric/sdk';

const textApi = api('text');

textApi.post('/send', async (ctx) => {});

The next step is pulling the environment variables in and constructing our messenger. We will use the dotenv module.

npm install dotenv

We can create a .env file in root of the project with the twilio API information that's sitting on your Twilio dashboard.

TWILIO_ACCOUNT_SID=14f7e9a0b95d11ec84220242ac120002
TWILIO_AUTH_TOKEN=6f20cb2ae2764be8b615d6fad4accec4
TWILIO_PHONE_NUMBER=+1234567890

The dotenv.config call will load the variables from the .env file into the process.env object. You can then use the variables to construct the messenger.

// functions/text.ts

import { api } from '@nitric/sdk';
import Messenger from '../common/messenger';

require('dotenv').config();

const textApi = api('text');

const twilioAccountSID = process.env.TWILIO_ACCOUNT_SID;
const twilioAuthToken = process.env.TWILIO_AUTH_TOKEN;

textApi.post('/sendMessage', async (ctx) => {
  const messenger = new Messenger(twilioAccountSID, twilioAuthToken);
});

We'll fill in the logic for the route. First, pull the data from the POST request. This data will look like so:

{
  "to": "+16505130514",
  "message": "Test Message from Twilio!"
}

And can be extracted from the context like this:

const { to, message } = ctx.req.json();

Secondly, convert this data to an SMS object:

{
  to,
  body: message ?? '',
  from: process.env.TWILIO_PHONE_NUMBER
}

Finally, putting all these components all together, we get a functional text messaging endpoint ready for testing:

// functions/text.ts

textApi.post('/send', async (ctx) => {
  const messenger = new Messenger(twilioAccountSID, twilioAuthToken);

  const { to, message } = ctx.req.json();

  const resp = await messenger.send({
    to,
    body: message ?? '',
    from: process.env.TWILIO_PHONE_NUMBER,
  });

  ctx.res.body = resp;

  return ctx;
});

Test the API

This API can easily be tested using the local Nitric dev environment. This is started with the following command:

npm run dev

Note: the dev script in the template starts the Nitric Server using nitric start and runs your functions.

We can then use a tool like postman or curl to test the endpoint.

curl -X POST -d '{"to":"+16505130514", "message": "Test Message from Twilio!"}' http://localhost:4001/send

If everything has been set up correctly, and the 'to' field on the JSON request body is replaced with a phone number you own, you will get a text that looks something like:

Sent from your Twilio trial account -
Test Message from Twilio!

Thats it! If you want to deploy the API you can using our deployment docs. If you want to attach a frontend to the application so its a bit more user friendly, you can use any framework you want or follow our Next.js guide