Extensions to the configurators, added when you need them: Logic for rules beyond formulas, and API/ERP integration for orders and documents straight inside your own system.
An add-on is not another product. It attaches to the configurator you already have, is billed monthly like a plan, and can be switched off at any time. What each one costs is in the price list.
Each add-on solves one thing. When you do not need it, you do not pay for it.
Always alongside a configurator, never on their own. An add-on extends what you already have — without a configurator it would have nothing to do. It attaches to any plan.
Monthly, on the same term as your plan. Paying a year in advance covers add-ons for the same eleven months instead of twelve. You can switch one off from the next period.
You can try them during the trial. The thirty free days carry full functionality, so you can find out whether you need an add-on before you decide on it.