Each one does a single thing the composer you are typing into will not tell you. No account, no trial, and nothing you type leaves your browser.
X does not count characters, it counts weight. Every URL costs 23 whatever its length, emoji and CJK cost 2 each. This counts the way X counts.
Most splitters cut to 280 and then append “1/7”, pushing every part over the limit they just measured against. This reserves the numbering first, and never cuts inside a link or an emoji.
Every platform’s hard limit and the point where the feed hides the rest — each marked by whether the platform documents it or people merely observe it. Check one draft against all five at once.
They are the parts of PostSiete that work without knowing anything about you, so there is no reason to put them behind an account. If they are useful, the same checks run inside the composer on five sites via PostSiete Lens, and the product they came from writes the drafts in your own voice. If they are not useful, you have lost nothing.
PostSiete Lens is a free Chrome extension that runs these same checks on X, LinkedIn, Instagram, Threads and Facebook while you type — including the fold line drawn where each one actually cuts. No account, no trial. It reads — it never posts for you.
Add to Chrome — free →