Features are part of the base plan subscription (depending on the plan), while add-ons and Surfer AI credits (the pay-as-you-go model) must be purchased on top of the plan subscription. The only exception is Max, as it includes all features and all add-ons, except for the Surfer AI credits.
‍List of all available features: Organization seats, Shareable articles, Plagiarism checker, Terms Assistant, and integrations with Google Docs, WordPress, and Jasper.
‍List of all available add-ons: Audit, SERP Analyzer, Whitelabel, Surfer API.
‍List of all pay-as-you-go options: Surfer AI, Content Editor overages (overages mean additional Content Editor credits that you can purchase on top of your subscription without the need for upgrading your plan).