Zotero-Write-Token: 19a4f01ad623aa7214f82347e3711f56

Zotero-Write-Token is an optional HTTP header, containing a client-generated random 32-character identifier string, that can be included with unversioned write requests to prevent them from being processed more than once (e.g., if a user clicks a form submit button twice). The Zotero server caches write tokens for successful requests for 12 hours, and subsequent requests from the same API key using the same write token will be rejected with a 412 Precondition Failed status code. If a request fails, the write token will not be stored.

If using versioned write requests (i.e., those that include an If-Unmodified-Since-Version HTTP header or individual object version properties), Zotero-Write-Token is redundant and should be omitted.