API Keys are secure tokens that are used to allow FlashDialler to communicate with your instance of ConnectWise Manage. This is the connection method that FlashDialler will use to access your data securely.
You will need to create a new API Security Role for the application and then connect it to an API Member (you are not charged by ConnectWise for this type of account). A "Public" and "Private" key which are both generated from ConnectWise Manage. You will need to make a note of these so you can add them to the FlashDialler setup page.