# Overview


Contact us to enable the custom code feature.

Custom code is a feature enabled by Chargebee that allows the merchant to implement custom business logic while the customer performs certain actions. Currently, this feature is supported in the customer portal in Edit Subscription using the functions fetchAllowedPlanConfig and fetchChangeSubscriptionOptions.

Custom code features supported:

  • Apply subscription changes immediately or at end of term using fetchChangeSubscriptionOptions.
  • Fetch applicable plans & addons for upgrade & downgrade. Automatically attach add-ons for selected plans, and add metadata for quantity restrictions using fetchAllowedPlanConfig.