How this free Threads post scheduler works
Draft a Threads post (up to 500 characters), pick a media type, choose who can reply, and set a publish time. The character counter is grapheme-aware so emojis count the way Threads enforces them.
Threads character limit (500)
Threads posts allow up to 500 characters — nearly double X. The counter on this page goes red the moment you exceed 500 so you know to trim or split into a Threads thread before scheduling.
Reply control on Threads
Threads lets you restrict replies to followers, only people you mention, or nobody. Pick a value here and Postmixr applies the matching reply_control field on the Threads Graph API at publish.