A character count is the difference you fix by trimming. Whether a post can exist without a picture, how many images it may carry, whether it expires and how much of it shows before the fold are differences you fix by making something else.
The character count is the platform difference that costs least to deal with, because trimming a sentence is a five-minute edit. The differences that cost real time are the ones that change what you have to produce: four of the eleven publishing channels refuse a post that carries no media at all, the image cap ranges from zero to thirty-five, one network deletes your post after a week, and one shows about two hundred characters before a fold. None of those is fixed by cutting words.
Four publishing channels reject a post with no media: Instagram, TikTok, Pinterest and YouTube. On those four, a picture or a video is not a nice-to-have attached to a caption — the caption is metadata on a media object, and without the object there is nothing to publish. This is the difference that decides whether a network is in your rotation at all, because it converts every post from a writing task into a production task. Facebook, LinkedIn, X, Threads, Bluesky, Mastodon and Google Business all accept text alone.
Comparing platforms on one axis hides the trade. Text length, media requirement, image cap and chain support pull in different directions, and a plan that only checks length will book a photo shoot it did not need or skip one it did. The table below is the set of hard limits recorded in the product's own platform rules, which is what an assistant reads before it drafts anything.
| Platform | Text limit | Media required | Images per post | Post chains |
|---|---|---|---|---|
| X | 280 (4000 on premium long posts) | No | 4 | Yes |
| Bluesky | 300 | No | 4 | Yes |
| Threads | 500 | No | 20 | Yes |
| Mastodon | 500 on most instances | No | 4 | Yes |
| 500 | Yes | 5 | No | |
| Google Business | 1500 | No | 1 | No |
| 2200 | Yes | 10 | No | |
| TikTok | 2200 | Yes | 35 | No |
| 3000 | No | 20 | No | |
| YouTube | 5000 description, 100 title | Yes | 0 | No |
| 63206 | No | 10 | No |
A rule changes the artefact when obeying it means making something different, not writing something shorter. These are the ones worth reading before a campaign is planned rather than after a draft is written:
A cross-network social report fails on two things: metrics that do not mean the same thing, and metrics that were never reported being stored as zero.
Publishing writes to a database and tells search engines about an address. Preflighting is the step that asks the server answering that address whether it serves a page. What to check, which findings block an announcement, and why the check must never fail a publish.
Market4 turns one release note into a changelog page, a blog post, a mail-out and a week of social posts — and then tells you which of them brought anyone back.
Writing one message for several networks works when the differences are lengths and fails when they are artefacts. A single idea can be trimmed from three thousand characters to two hundred and eighty and still be the same idea; it cannot be trimmed into a vertical video. The workable split is to decide the media first — none, one image, a set, a video — because that decision selects which channels are even eligible, and only then to write the text at the shortest limit in the set you chose.
Chain support is the other axis that changes the shape of a draft rather than its length. X, Threads, Bluesky and Mastodon support post chains, so a long argument survives there as a sequence. LinkedIn, Facebook, Instagram, Pinterest, TikTok, YouTube and Google Business do not, so on those the same argument has to be cut to one post or moved into an image.
Instagram, TikTok, Pinterest and YouTube will not publish a post that carries no media. On those platforms the text is a caption or description attached to a media object, so there is nothing to publish without the object. Facebook, LinkedIn, X, Threads, Bluesky, Mastodon and Google Business all accept a text-only post, though several of them will show a link preview card if the text contains a URL.
X downscales images to a thousand pixels. A screenshot of a dashboard or a table that is legible at full size loses its small text at that width, which is why a screenshot that works as a LinkedIn document or an Instagram carousel often does not survive as an X image. Cropping to the part that matters before uploading is more reliable than uploading the whole screen and hoping.
No. A Google Business post expires after seven days and disappears from the profile, and each post is one of three kinds — What's new, Event or Offer — which take different fields. Posts are also reviewed by Google before they appear, and the profile has to be verified before anything can be published at all. A profile that is posted to monthly is empty for three weeks in four.
It is the wrong first question. Media requirement decides eligibility, because four channels cannot take a text-only post at all, and image dimensions and chain support decide whether a given piece of work can exist on a given network. Length decides only how much editing the same idea needs once those questions are settled, and that editing takes minutes.
An agent writing at volume will run out of evidence long before it runs out of topics. There are three honest moves at that point, and inventing a plausible figure is not one of them.