# Usage

To access API.1 (Consent API and Accounting API), you must create an API Key. You create and manage API Keys in the [Client Portal](https://docs.zwapgrid.com/client-portal/api-keys) per [environment](https://docs.zwapgrid.com/client-portal/environments).

### Pass the key in requests

When you call API.1, pass your API Key in every request using the `x-api-key` HTTP header:

```
x-api-key: YOUR_API_KEY_HERE
```

Replace `YOUR_API_KEY_HERE` with the key you created in the Client Portal. Use a **Development** key for Development consents and sandbox data (e.g. Test.1); use a **Production** key for Production consents and live data from Your Customer's Accounting Systems.

For full request conventions, correlation IDs, and authentication, see [Get Started](https://docs.zwapgrid.com/get-started/get-started).