Short answer: X has never published one, and you can keep saving past a thousand posts without hitting a wall. The longer answer is that a ceiling shows up anyway, just not the one people are looking for.
Nothing. There's no documented maximum number of bookmarks, no warning when you're approaching one, and no message telling you the list is full. As far as saving goes, the bookmark button keeps working.
That's why the question is confusing. People search for the limit because their bookmarks stopped behaving, then find no official number and assume they misremembered.
It's a reading limit, not a saving one. The bookmarks timeline loads a batch at a time, and it reliably stops fetching older entries a few hundred deep. Developers working against X's bookmarks endpoint describe it topping out around 800 posts, and the app behaves much the same way: you scroll, the spinner turns, nothing more arrives.
The saves themselves aren't gone. Tools that read bookmarks through a logged-in session routinely pull far more than the app will show. But if the only way you have to reach a bookmark is scrolling the list, then whatever the list stops showing is functionally deleted.
Long before any of that, there's a plainer problem. The bookmarks screen has no search, no tags, and no folders unless you pay for Premium. So the practical ceiling is however many posts you can still find by scrolling and recognising, and for most people that number is in the low hundreds at best.
Past that, bookmarking still feels productive and stops being useful. You save something, it drops onto a pile you'll never dig through, and the next time you need it you search Google instead.
Two things worth doing while your list is still reachable.
Zihin does both. A Chrome extension reads your bookmarks through your own logged-in browser session and copies them into your library, where they're searchable by meaning rather than exact wording, tagged into topics automatically, and kept after the original post is deleted. There's no scroll ceiling on your own copy, and no Premium subscription in the way.
Free during beta · Your X credentials never touch our servers