In order to use the REST API you need to provide api credentials, more specifically consumer key and consumer secret. There are two ways to supply this important information: HTTP Basic Auth or as a Query parameters, each of them are explained below.
The consumer key and consumer secret can be obtained by creating API Key in the Settings > API Keys section as seen in Figure 1.
1.1. HTTP Basic Auth
This is example of how to create your Authentication with HTTP Basic Auth:
Note: base64() is common function that encodes string to Base64 format and exists on every platform.
1.2. Query Parameters
Simply provide consumer_key and consumer_secret as query string parameters.
Example url will look like this: