# Connect your application

*Chapter 01 of 06 · UAE*

You are adding e-invoicing to your accounting product. First, give your backend a secure way to talk to Complyance.

> **Before you start**
>
> Have access to an ISV workspace. This walkthrough uses sandbox credentials and a UAE customer throughout, then moves to production in its last chapter.
>
> Onboarding a company through Connect is available for the United Arab Emirates only. For a customer in Saudi Arabia, Malaysia, Belgium or Germany, add the company from **Onboard** in the Client Portal, following the country’s onboarding guide in [Countries](https://docs.complyance.io/countries/). Then prepare and submit its invoices as in chapters 3 to 5, with that country’s code and payload.

## Create your sandbox API key

In the Partner Platform Developer portal, open **API Keys** and create a sandbox key with read and write access. Copy the secret when it appears; it is shown only once.

## Keep the key on your server

Store it in your server-side secret manager. Load it as `COMPLYANCE_API_KEY` when running the examples in this guide.

## Use the right header for each API

You will use Connect to onboard the customer, then Unify to submit their invoice. Both use the same key, with different authentication headers.

```http title="Connect · Company onboarding"
X-API-Key: ${COMPLYANCE_API_KEY}
```

```http title="Unify · Invoice submission"
Authorization: Bearer ${COMPLYANCE_API_KEY}
```

> **You are ready for the next chapter**
>
> Your sandbox key is stored securely. Next, you will create the customer’s company and the Source that identifies your integration.

[Authentication & environments reference ↗](https://docs.complyance.io/api-reference/authentication/)

---

**Next chapter (02):** [Onboard your customer](https://docs.complyance.io/partner-platform/isv/first-uae-invoice/onboard/). Create the company and check that it is ready for invoicing.

Source: https://docs.complyance.io/partner-platform/isv/first-uae-invoice/connect/