Preview a prorated plan change

How to use the Try It feature

Use the built-in API explorer to test this endpoint directly in your browser.

Task	Instructions
Authenticate	Locate the CREDENTIALS section on the right. Enter your username and password to ensure the request is authorized.
Select Example	Use the EXAMPLES drop-down menu to load a pre-configured request body. The JSON payload will update automatically.
Customize Data	Modify the JSON fields in the BODY PARAMS section. Your changes update the request preview instantly.
Execute	Click the Try It! button to send the API request and view the real-time response below.

Request body examples and use cases

All of the request examples listed below can be selected from the EXAMPLES drop-down menu in the top-right corner of the Try It! feature.

Request Example	Use Case
Estimate Subscription	Estimate the total cost of a subscription, including the base product, add-ons, pricing in multiple currencies, proration, and applied coupons.
Upgrade Plan	Upgrade a subscription from a lower-tier plan (e.g., "basic") to a higher-tier premium plan.
Downgrade Plan	Downgrade a subscription from a higher-tier plan (e.g., "premium") to a lower-tier basic plan.
Add-On Quantity Change	Increase the quantity of an existing add-on in a subscription.
Complex Subscription Change	Modify multiple aspects of a subscription at the same time, including: Updating the plan’s quantity and price Adjusting add-on quantities and prices Applying discounts to new or existing add-ons Getting an updated cost estimate

Error handling

This table lists errors you may encounter when working with this endpoint and provides solutions to help you troubleshoot.

Status	Error Message	Solution
`400`	`Request must contain a single root object.`	Ensure the request payload contains a single root object.
`400`	`Request must contain a subscription ID.`	Ensure the `subscription` ID is included in your request payload.
`400`	`Proration is not allowed for this subscription.`	Check the subscription's eligibility for proration.
`400`	`Refund exceeds the last charge amount.`	Ensure the refund amount does not exceed the last charge amount.
`404`	Subscription ID does not exist: `[{subscriptionId}]`	Verify the `subscription` ID is correct and exists.
`500`	`Subscription is not changeable`	Verify that the `subscription`ID is changeable, or try again with a different subscription.

200OK