It is important to choose the correct authorization path for your integration. An integration either authorizes to an individual username, or to an organization wide Application in the Writer platform. This will affect who the activity in reports is attributed to.
If the integration is designed to support a user as they create and edit content; this API with the username password login flow should be used. To manage inactivity timeouts; a new token can be provided in the response to any of the Rest API requests. Whenever a X-AUTH-TOKEN header is present in a Rest API response, the integration should use this new token in subsequent requests.
If the integration is designed to support a review stage where content is coming from multiple different users; then a Writer Application should be created. This is done within the Writer platform, go to the Admin Panel and select Developer Integrations from the left side bar. The validity of the token is specified during creation, and these tokens do not have an idle timeout; so no new token will be provided in response headers.