# One-Time Add-Ons APIs for managing one-time product additions to upcoming subscription orders, including adding, retrieving, and removing one-off items ## saveOneOffBy - [PUT /memberships/cp/api/subscription-contract-one-offs-by-contractId-and-billing-attempt-id](https://developers.membership.appstle.com/storefront-api-swagger/one-time-add-ons/saveoneoffby.md) ## getOneOffsForSubscriptionContract - [GET /memberships/cp/api/subscription-contract-one-offs-by-contractId](https://developers.membership.appstle.com/storefront-api-swagger/one-time-add-ons/getoneoffsforsubscriptioncontract.md)