# Try It!

Every operation described in these API References has a **Try It!** button as seen below.

![Try It! Button](/assets/try-it-button.5335883b80c8643e3aed3d7e13149c3189547539463ced9a75a2a35314f86bf9.6a7813e3.jpg)

## Mock Server

By default, API calls will be executed against the **Mock server environment** which will not create, update, delete, process, or return any real data.
Instead, any calls to the **Mock server** will return sample JSON that mimics the structure you might expect from a live API call.

We suggest getting started by making calls to the **Mock server** and exploring the responses.

## Set Your Tenant ID

When you click on the **Try It!** button, you will see a popup window with a REST client where you can test API calls.
You should start by selecting the `{{tenantId}}` variable and setting your Rhythm Tenant ID as seen below.

![Setting Rhythm Tenant ID](/assets/tenant-id.3cd9cfd740fec1dde529235050a36fc0a3135407996ffa0565d26693534aa6eb.6a7813e3.jpg)

## Environments

The REST client supports multiple **environments**. Each environment will send requests to a different host, either the **Mock server** or the **Live API**.

The active environment can be seen or changed in the upper right corner of the REST client. **Variables** are defined within the active environment.
You can see or modify the variables for the active environment by clicking the **Environments** tab.

![Selecting Your Environment](/assets/environments.3a68fb979fc763283e9de774c15bc9d1d5281c36adc505c1790b785aa03bc79d.6a7813e3.jpg)

Since variable definitions are stored within the environment, you may need to re-set variables, including **Rhythm Tenant ID**, after changing environments.

## Live API

If you would like to use the REST client to make calls to the **Live API**, select the Live API URI under the Environment drop down in the upper right corner.

To make calls to the **Live API**, you will need to generate an authorization token using the authorization flow that best matches your use case. For more information, see the Quick Start section about [Authentication](/tutorials/authentication).

Next, confirm that the `Authorization type` is set to `JWT` by navigating to the **Security** tab. You can then add your authorization token value in the `Bearer Token` field by setting the `{{knox-authorizer_token}}` variable.

At this point, you should be able to execute a live API call.