Application of a credit memo by source invoice item

Learn how to apply a credit memo by source invoice item.

The Apply Credit to Source Item rule lets you apply a credit memo back to the original invoice item it references. This rule helps preserve item-level accuracy by applying each credit memo item to its corresponding source invoice item instead of distributing the credit more generally across the invoice.

If the credit memo includes tax items, Zuora also applies each credit tax item to the matching invoice tax item. Tax matching is based on the tax attributes associated with the item.

Benefits

Using this rule helps you:

Preserve the relationship between a credit memo item and its original invoice item
Apply tax amounts to the correct invoice tax items
Improve auditability and reconciliation
Make credit application behavior more predictable

Before using this rule, make sure that:

The credit memo is being applied to an invoice
Only one invoice is included in the application
The credit memo items reference valid source invoice items
The balances on credit memo items and tax items do not exceed the balances on their matching invoice items or tax items

Credit application matching logic

When you use Apply Credit to Source Item:

Each credit memo item is matched to an invoice item using its source item reference
Each credit tax item is matched to an invoice tax item using tax attributes

Tax items are matched using this tax key:

Tax name
Tax location code
Tax jurisdiction
Tax rate

If multiple credit memo items reference the same invoice item, Zuora uses proration to apply them. If multiple matching tax items are found, proration is also used.

Items with a zero balance are skipped during application.

To know how to apply a credit memo in the UI, refer to Apply a credit memo in the UI.

Apply a credit memo with the REST API

You can also use this rule when applying a credit memo through the REST API.

Include the applicationRule field in the request body and set it to ApplyCreditToSourceItemRule.

This is an example request:

{
  "effectiveDate": "2026-01-30",
  "applicationRule": "ApplyCreditToSourceItemRule",
  "invoices": [
    {
      "invoiceId": "8ad097b490a1ec740190a5aaece25734",
      "amount": 11
    }
  ]
}

Supported scenarios

This rule supports scenarios such as:

Applying a credit memo to a single invoice
Applying item-level credits back to their source invoice items
Applying credit tax items to matching invoice tax items
Applying tax-only credit memos
Applying credit memos that include positive and negative items
Applying multiple credit memo items that reference the same invoice item

Limitations

This rule does not support:

Applying a credit memo to multiple invoices in one request
Applying a credit memo to a debit memo
Including item-level application data in the same request
Using a different application rule together with this rule
Partial application when the apply amount does not match the credit memo’s unapplied amount

The following are also out of scope:

Invoice write-off behavior as part of this rule
Payment run application
Order-related credit memo application flows

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