To access your API Keys, simply click the dropdown menu titled with your Username and the person icon in the top right of the site. Here you can select API Keys from the dropdown.
On the API Key page you can see a list of API keys and their secrets associated with your TradeSync account. These API Keys are used just like usernames and passwords when trying to communicate with the TradeSync API.
Authenication via the API is explained here
An API Key can be copied via the purple Copy icon.
An API Key's secret can be copied via the blue Copy icon.
You can revoke API access from a user or application by deleting the API key from your list. This is done by pressing the red Trash can icon.