Electronic invoicing with JavaScript

This tutorial builds two simple Node.js applications from scratch:

Receive: connects and authenticates with the Invoicetronic API and downloads any new incoming invoices.
Send: connects and authenticates with the Invoicetronic API and sends an invoice to the SDI.

Before continuing, make sure all the prerequisites below are met.

Prerequisites

We assume that these prerequisites are met:

Node.js has been downloaded and installed
You obtained an active API Key
You registered with the Italian Revenue Service (needed for the live environment)

We use Node.js and npm as they are the de facto standard for server-side JavaScript, but the examples work with other compatible runtimes as well.

Tip

For an optimal JavaScript experience, consider using VS Code which offers excellent Node.js support. Make sure the JavaScript/Node.js extension is active.

Did you know?

The JavaScript SDK supports both modern async/await and traditional Promises, giving you flexibility in your programming style.

Receive

Create the app

The first step is to create the application directory and initialize the Node.js project:

mkdir receive && cd receive

Initialize the project with npm:

npm init -y

The command created a new Node.js project with a package.json file in the current directory.

Install the SDK

Install the Invoicetronic JavaScript SDK:

npm install @invoicetronic/js-sdk --save

Once that's done, open VS Code in the current directory:

code .

Configure the SDK

Create a new file called index.js and add the following code:

Configure the SDK

const invoicetronicSdk = require('@invoicetronic/js-sdk');

// Configure the SDK
const apiClient = invoicetronicSdk.ApiClient.instance;
const basicAuth = apiClient.authentications['Basic'];
basicAuth.username = 'YOUR TEST API KEY (starts with ik_test_)';

apiClient.basePath = 'https://api.invoicetronic.com/v1';

As you can see, we configure the SDK by setting the API's base path and your test API Key (not the live one). Notice how we use the username property to set the API Key.

API Key comes in pairs

When you create your account, you obtain a pair of API Keys. One is the test key for the API Sandbox, and the other is the live API's. You can tell the difference because the former starts with ik_test_, while the latter begins with ik_live_. In this tutorial, always use the test key.

Download invoices

We are ready to make a request. We want to download new vendor invoices that may be available from the SDI. Add these lines:

Download unread invoices

const fs = require('fs');

// Download unread invoices
const receiveApi = new invoicetronicSdk.ReceiveApi();

async function downloadInvoices() {
  try {
    const opts = {
      'unread': true,
      'includePayload': true
    };

    const inboundInvoices = await receiveApi.receiveGet(opts);
    console.log(`Received ${inboundInvoices.length} invoices`);

    for (const invoice of inboundInvoices) {
      if (invoice.encoding === 'xml') {
        fs.writeFileSync(invoice.fileName, invoice.payload, 'utf8');
      } else if (invoice.encoding === 'base64') {
        const buffer = Buffer.from(invoice.payload, 'base64');
        fs.writeFileSync(invoice.fileName, buffer);
      }

      console.log(`Downloaded ${invoice.fileName} from a vendor with VAT ID ${invoice.prestatore}`);
    }
  } catch (error) {
    console.error('Error:', error.message);
  }
}

downloadInvoices();

Payload Inclusion

We set includePayload: true to retrieve the actual invoice content in the payload property. Without this parameter, the payload field would be null by default, which increases performance and reduces response size when you only need metadata.

In the terminal, run the application:

node index.js

You should obtain an output similar to this one:

Received 3 invoices
Downloaded file1.xml from a vendor with VAT ID IT06157670966
Downloaded file2.xml.p7m from a vendor with VAT ID IT01280270057
Downloaded file3.xml.p7m from a vendor with VAT ID IT01280270057

The files are in the current directory, ready for you to inspect them.

Not receiving invoices in the live environment?

Ensure you registered with the Italian Revenue Service, which is a requirement for the live environment.

What we learned

In this example, we learned several things.

We must configure the SDK by setting both the basePath and basicAuth.username authentication, the latter initialized with the API key.
We must instantiate a class representing the endpoint we want to work with. In this case, we leverage ReceiveApi to download incoming invoices.
Endpoint classes like ReceiveApi offer methods for interacting with their target entity. We call receiveGet to retrieve invoices. Because we only want new, unread invoices, we pass unread: true. We also pass includePayload: true to retrieve the actual invoice content.
Invoice objects expose valuable properties such as encoding, fileName, and payload. The last one contains the invoice content, as plain text or Base64-encoded, as described by encoding.

Source Code on GitHub

The source code for this Quickstart is also available on GitHub.

Send

Create the app

The first step is to create the application directory and initialize the Node.js project:

mkdir send && cd send

Initialize the project with npm:

npm init -y

Install the SDK

Install the Invoicetronic JavaScript SDK:

npm install @invoicetronic/js-sdk --save

Once that's done, open VS Code in the current directory:

code .

Configure the SDK

Create a new file called index.js and add the following code:

Configure the SDK

const invoicetronicSdk = require('@invoicetronic/js-sdk');

// Configure the SDK
const apiClient = invoicetronicSdk.ApiClient.instance;
const basicAuth = apiClient.authentications['Basic'];
basicAuth.username = 'YOUR TEST API KEY (starts with ik_test_)';

apiClient.basePath = 'https://api.invoicetronic.com/v1';

As you can see, we configure the SDK by setting the API's base path and your test API Key (not the live one). Notice how we use the username property to set the API Key.

API Key comes in pairs

When you create your account, you obtain a pair of API Keys. One is the test key for the API Sandbox, and the other is the live API's. You can tell the difference because the former starts with ik_test_, while the latter begins with ik_live_. In this tutorial, always use the test key.

Send an invoice

We are ready to make a request. We want to send an invoice to the SDI. Add the following code:

Send an invoice

const fs = require('fs');
const path = require('path');

// Send an invoice
const filePath = '/some/file/path/filename.xml';

const metaData = {
  'internal_id': '123',
  'created_with': 'myapp',
  'some_other_custom_data': 'value'
};

const sendApi = new invoicetronicSdk.SendApi();

async function sendInvoice() {
  try {
    const sendData = new invoicetronicSdk.Send();
    sendData.fileName = path.basename(filePath);
    sendData.payload = fs.readFileSync(filePath, 'utf8');
    sendData.metaData = metaData;

    const sentInvoice = await sendApi.sendPost(sendData);

    console.log(`The invoice was sent successfully, it now has the unique Id of ${sentInvoice.id}.`);
  } catch (error) {
    console.error('Error:', error.message);
  }
}

sendInvoice();

In the terminal, run the application:

node index.js

You should obtain an output similar to this one:

The invoice filename.xml was sent successfully, it now has the unique Id of 123.

What we learned

In this example, we learned several things.

We must configure the SDK by setting both the basePath and basicAuth.username authentication, the latter initialized with the API key.
We must instantiate a class representing the endpoint we want to work with. In this case, we leverage SendApi to send invoices. Endpoint classes like SendApi offer methods for interacting with their target entity. We call sendPost to send an invoice.
The Send class exposes valuable properties such as fileName, metaData, and payload. The last one contains the invoice content, while metaData is optional and binds custom data to the document.

Source Code on GitHub

The source code for this Quickstart is also available on GitHub.