A sessionToken can be obtained by using either of the Betfair Exchange API login methods - non-interactive and interactive login.
For testing purposes you can also retrieve the sessionToken from your web browser (while logged into the Betfair website). Please see instructions below:
There are several ways that you can obtain a session token for the provided API Demo Tools.
Using the pre-populated session token from the Betfair website
The Demo Tools will populate the session token field with the value of a session token found in your browsers cookie store for the Betfair.com website. Login to www.betfair.com (via a seperate browser tab) and refresh the demo tools page to automatically input the Session Token field
Manually adding the ssoid (session token) from the website cookie.
Using Google Chrome you can inspect and copy the session directly from the browser by doing the following:
1, Press Ctrl+Shift+J
2. Select Application > Cookies > www.betfair.com or www.betfair.com.au
3. Copy the Value for the cookie with name ssoid and paste this into the Demo Tool