Content negotiation switchover to REST API - Wednesday, 13 October
Scheduled Maintenance Report for Crossref
The scheduled maintenance has been completed.
Posted Oct 13, 2021 - 17:00 UTC
Verification is currently underway for the maintenance items.
Posted Oct 13, 2021 - 16:16 UTC
In progress
Scheduled maintenance is currently in progress. We will provide updates as necessary.
Posted Oct 13, 2021 - 16:00 UTC
On 13 October, we will be making backend changes to our content negotiation service, effectively folding it into our REST API. While behavior should be unchanged for requests made according to the specification, there are a few functional changes to note.
1) The resolver URL will change from to
2) Content negotiation responses will be returned by one of our three API pools depending on whether you include mailto identification in your user agent header for the polite pool, or include a token for Metadata Plus subscribers accessing the Plus pool. All other requests will be serviced by the public pool.
Posted Oct 12, 2021 - 18:26 UTC
This scheduled maintenance affected: APIs (Content negotiation).