Electronic invoicing with Python

This tutorial builds two simple Python 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:

Python 3.9+ has been downloaded and installed
pip is installed (comes with Python)
You obtained an active API Key
You registered with the Italian Revenue Service (needed for the live environment)

We use pip for dependency management, which is the de facto standard for modern Python.

Tip

For an optimal Python experience, consider using VS Code with the Python extension or PyCharm for a complete IDE.

Did you know?

The Python SDK supports type hints and Pydantic validation, providing runtime checks and better IDE autocomplete.

Receive

Create the app

The first step is to create the application directory:

mkdir receive && cd receive

Install the SDK

Install the Invoicetronic Python SDK:

pip install invoicetronic-sdk

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

code .

Configure the SDK

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

Configure the SDK

import invoicetronic_sdk
from invoicetronic_sdk.rest import ApiException

# Configure the SDK
configuration = invoicetronic_sdk.Configuration(
    username='YOUR TEST API KEY (starts with ik_test_)',
    host='https://api.invoicetronic.com/v1'
)

As you can see, we configure the SDK by passing your test API Key (not the live one) and the API host. Notice how we use the username parameter 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

import base64

# Download unread invoices
with invoicetronic_sdk.ApiClient(configuration) as api_client:
    receive_api = invoicetronic_sdk.ReceiveApi(api_client)

    try:
        inbound_invoices = receive_api.receive_get(
            unread=True,
            include_payload=True
        )

        print(f"Received {len(inbound_invoices)} invoices")

        for invoice in inbound_invoices:
            if invoice.encoding == 'Xml':
                with open(invoice.file_name, 'w', encoding='utf-8') as f:
                    f.write(invoice.payload)
            elif invoice.encoding == 'Base64':
                with open(invoice.file_name, 'wb') as f:
                    f.write(base64.b64decode(invoice.payload))

            print(f"Downloaded {invoice.file_name} from a vendor with VAT ID {invoice.prestatore}")

    except ApiException as e:
        print(f"Error: {e}")

Payload Inclusion

We set include_payload=True to retrieve the actual invoice content in the payload property. Without this parameter, the payload field would be None by default, which increases performance and reduces response size when you only need metadata.

In the terminal, run the application:

python index.py

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 creating a Configuration instance and passing username (API key) and host (API URL).
We use the with context manager to automatically handle API client closure. We instantiate ApiClient passing the configuration.
We must instantiate a class representing the endpoint we want to work with. In this case, we leverage ReceiveApi to download incoming invoices, passing the API client.
Endpoint classes like ReceiveApi offer methods for interacting with their target entity. We call receive_get() to retrieve invoices. Because we only want new, unread invoices, we pass unread=True. We also pass include_payload=True to retrieve the actual invoice content.
Invoice objects expose attributes like encoding, file_name, 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:

mkdir send && cd send

Install the SDK

Install the Invoicetronic Python SDK:

pip install invoicetronic-sdk

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

code .

Configure the SDK

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

Configure the SDK

import invoicetronic_sdk
from invoicetronic_sdk.rest import ApiException
from invoicetronic_sdk.models.send import Send

# Configure the SDK
configuration = invoicetronic_sdk.Configuration(
    username='YOUR TEST API KEY (starts with ik_test_)',
    host='https://api.invoicetronic.com/v1'
)

As you can see, we configure the SDK by passing your test API Key (not the live one) and the API host. Notice how we use the username parameter 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

import os

# Send an invoice
file_path = '/some/file/path/filename.xml'

meta_data = {
    'internal_id': '123',
    'created_with': 'myapp',
    'some_other_custom_data': 'value'
}

with invoicetronic_sdk.ApiClient(configuration) as api_client:
    send_api = invoicetronic_sdk.SendApi(api_client)

    try:
        with open(file_path, 'r', encoding='utf-8') as f:
            payload = f.read()

        send_data = Send(
            file_name=os.path.basename(file_path),
            payload=payload,
            meta_data=meta_data
        )

        sent_invoice = send_api.send_post(send_data)

        print(f"The invoice was sent successfully, it now has the unique Id of {sent_invoice.id}.")

    except ApiException as e:
        print(f"Error: {e}")

In the terminal, run the application:

python index.py

You should obtain an output similar to this one:

The invoice 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 creating a Configuration instance and passing username (API key) and host (API URL).
We use the with context manager to automatically handle API client closure. We instantiate ApiClient passing the configuration.
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 send_post() to send an invoice.
The Send model exposes attributes like file_name, meta_data, and payload. The last one contains the invoice content, while meta_data is optional and binds custom data to the document.

Source Code on GitHub

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