Important Notes about PUT on Custom List Items

  1. Unlike all other PUTs, you cannot update a single list item using the primary key custom_list_item_id. Instead the PUT uses list_id to indicate which list is being operated upon.

  2. When processing a PUT with an array of list items, all existing list items in the list are deleted. The PUT replaces the items entirely. To append new items to an existing list, use the POST method.

  3. To add list items to an existing list using a bulk file (csv or txt) use the POST method.

  4. To update the value field of a list item you must replace the entire list using the PUT.