Glossary
Add-on
An add-on is a one-time fixed charge applied outside the recurring plan, used for things like setup fees, professional services or one-off purchases.
Add-ons sit alongside subscriptions and usage rather than replacing them, and they typically appear on a one-off invoice or as an extra line on a periodic one.
They are the pragmatic answer to the charge that does not fit the pricing model, which most enterprise contracts eventually contain.