Every request requires a Personal Access Token, or API Token, to authenticate.
This token will map to one specific ProductPlan user. If your account has multiple users, make sure to choose a user who has the appropriate authorization you will need in order to perform the tasks you require of the API (i.e. a user with edit access to the roadmap in question).
Generating a Token
In the ProductPlan application, navigate to the custom integration settings. Follow the instructions for generating the key. Once the 64 character unique hash key is created and displayed, copy it somewhere safe and use it for authentication to the API.
Using a Token
For example, if your generated token is 0c8e87e3e4bb1c3f5c5acfbe7647e7651c31ac3114a67ee8512547e4fc416177, you would use it to authenticate with an Authorization header like this:
Authorization: Bearer 0c8e87e3e4bb1c3f5c5acfbe7647e7651c31ac3114a67ee8512547e4fc416177
Please note that the word Bearer must be included in the value and that there is one (and only one!) space between Bearer and the token.