Log in and click the Settings icon on the upper right-hand corner of any page.
Click Dev Center in the left menu.
Select API Credential Management.
Click the Create New API Key button.
Select Harvest for the API Type. Enter a description for the API key and click Manage Permissions.
Click the Copy button, and paste the API key below.
Click I have stored the API key.
Select your permissions. Either click Select All or select the relevant permissions required for this app.