Posting limitations are based on the type of subscription you have on Twitter / X. If you go over you will be prevented from posting and scheduling.
Premium Users
If you're an X Premium user, you can publish up to 50 long form posts in a thread, each with 25,000 characters per post.
š” If you need rich formatting, such as headings, lists, quotes, inline images, or videos, create an X Article instead. Typefully lets you write, schedule, and publish X Articles directly.
Non-Premium / Free users
Free Twitter / X users can publish up to 50 posts in a thread with up to 280 characters per post.
X Articles are not available for free X accounts. If your account is not eligible, X may reject the article when Typefully tries to publish it.