The AI extension is added to the Smart plan and is priced in proportion to your monthly sending volume, starting from €9.90 per month on the annual plan. It follows the same rules as the other extensions: on semi-annual or quarterly plans the monthly cost is higher, while on pay as you go it is a one-off. You will find the details in the Extensions price list and can calculate it in the plan calculator. You need a compatible AI assistant: today ChatGPT with a Plus plan or higher, while other assistants are pending approval.