The editor changes per platform
Postiz offers different formatting depending on what the selected platform accepts. You are not seeing an inconsistent interface, you are seeing what that platform can carry.
Telegram is a special case: it takes markdown but not headings, so the heading
buttons are hidden.
Character counts
The counter under the editor shows the limit for the selected channel, and it is media-aware, so attaching an image can change the number on platforms that charge characters for links or media. Limits vary enormously: Bluesky 300, X 280 (4,000 verified, 100,000 in article mode), Mastodon 500, LinkedIn 3,000, Facebook 63,206. The full list is in Posting rules by platform. If you are over the limit on one channel only, detach that channel rather than cutting the text everywhere. See Global vs per-channel.Mentions
Type@ to mention someone. Postiz queries the platform for matching
accounts and inserts a real mention, not just text.
Mentions only work on a detached channel. In the Global tab there is no
single platform to resolve the handle against, so the suggestion list does not
appear.
Emoji
The emoji picker sits in the toolbar and follows your light or dark theme. You can also paste emoji directly.Signatures
The signature button inserts a saved block of text. If one of your signatures is marked auto-add, it is already in the editor when the composer opens. Manage them in Settings, see Sets and signatures.Links
Postiz validates links as you type and rejectsftp:, file: and mailto:
schemes, plus anything that looks like a bare email address.
What happens to the links you do add depends on your short link preference and
the platform. See Links and validation.