Not sure if they have an API

Instagram announced last week that an API will be available by June 2024. Buffer said they are working on an integration. So with the number of downloads of Threads double that of Twitter, it becomes increasingly important to integrate Threads.

API is documented, but not open for everyone: https://developers.facebook.com/docs/threads/

The Threads API went live yesterday: https://developers.facebook.com/blog/post/2024/06/18/the-threads-api-is-finally-here/

Looks like Buffer has launched their Threads integration too: https://buffer.com/threads

Feedhive also have done it - https://www.threads.net/@simonhoiberg/post/C8jGmZhoONZ