The body of the request is the JSON key-value metadata to patch to the ACH return. Do not use the metadata field to store sensitive or confidential data.

Updating metadata will merge with the existing metadata stored on the ACH return by the top-level key. If the same top-level key is passed in this request, it will overwrite the value stored on the ACH return. Only keys included in the payload will be updated. To remove a key, set the key's value to null. To remove all metadata pass null for the metadata value.

ACH return Metadata must be less than 8 KB in size.

ACH return metadata can only be updated using an API key. This request should not be made by your frontend and should only be done by backend logic that only the platform can complete.