You'll need to include an Authorisation bearer token in the header with every request you make to the Intruder API.
Authorisation tokens are personal access tokens, i.e. they are linked to your Intruder user account.
To generate a personal access token, head to Account > Settings and click the tab for the Team Account page in the Intruder portal.
Once you are here, click the "Create Access Token" button, enter a name that describes what this token will be used for and (optionally) specify an expiry date after which the token will automatically be revoked.
You will then be prompted to enter your Intruder User Account password, and select "Confirm Password"
And that's it! Your new token will be created and shown below. Once you've created the access token, please ensure you save the token in a safe place (e.g. a password manager) as you won't be able to access it again.
If you need to revoke the access token at any time, just click the trash can icon on the right under the 'Active Access Tokens' section.
For more information on how to use the Intruder API, please check out the Intruder Developer Hub.