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Scroll down to Users and expand the Users sub-menu then Users/sign_in.
Click Try it out. The platform displays username and password fields that correspond with a username and password used to log in to your PE3 instance.
Enter the login information and then click Execute. You should find the token string at the beginning of the response.
Note:
The user’s login name (email) and the user’s password are displayed in the output.
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Once you have the Token, it can be used is to authenticate all the other API requests.