> ## Documentation Index
> Fetch the complete documentation index at: https://stripe-invoice-custom-fields-docs.vinaka-apps.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Installation

> Install and activate the Invoice Custom Fields app.

## Prerequisites

Before installing, make sure you have:

* a Stripe account where apps can be installed,
* permission to manage invoices and customers in Stripe.

## Step 1: Install the app in Stripe

1. Install the app from the Stripe App Marketplace.
2. Open **App settings** after installation.
3. Confirm the app has access to required Stripe scopes.

## Step 2: Start your subscription

In the app settings:

1. Open the **Billing** tab.
2. Click **Start subscription** to begin your 14-day free trial.
3. Complete checkout and return to Stripe.

<Tip>
  If you're using the app in a Stripe Sandbox account, no subscription is needed. You can test freely.
</Tip>

## Step 3: Enable the app

In the app settings:

1. Open the **Configuration** tab.
2. Toggle **Enable app** to activate the app.
3. Configure your field mapping rules (see [Configuration](/getting-started/configuration)).
4. Click **Save**.

## Step 4: Validate end-to-end

1. Create a test invoice in Stripe with metadata matching your configured source keys.
2. Check that the custom fields are automatically filled on the draft invoice.
3. Open the invoice detail page and verify the sync status in the app panel.

## Where the app works

The app supports three environments, all activated by installing the app once:

| Environment   | What it is                                              | Subscription required?             |
| ------------- | ------------------------------------------------------- | ---------------------------------- |
| **Sandbox**   | Stripe Apps sandbox account (separate test environment) | No                                 |
| **Test mode** | Your regular Stripe account toggled to test mode        | No                                 |
| **Live**      | Your regular Stripe account in live mode                | Yes (€10/month, 14-day free trial) |

Sandbox and test mode are free for testing as long as you need. Production/live mode requires an active subscription before fields can be enabled.