| X | ||
|---|---|---|
| Characters | 3,000 | 280 |
| Media | optional | optional |
| Hashtags | 3 hashtags (5 max) at the end | 1-2 hashtags, zero is fine |
| Links in body | suppress reach | suppress reach |
| Needs platform approval | yes | yes |
LinkedIn allows 3,000 characters; X caps at 280. A post written to LinkedIn's length gets truncated — usually mid-sentence — unless it is rewritten, not trimmed.
LinkedIn: 3 hashtags (5 max) at the end. X: 1-2 hashtags, zero is fine. Carrying the tag block across is the single most obvious sign of an automated cross-post.
LinkedIn is professional and first-person; the hook must fit in 210 characters. X is one hook and nothing else — opinionated, conversational, over in a breath. Those are different jobs, so the same words cannot do both well — and every algorithm here demotes text that obviously was not written for it. The fix is not to skip cross-posting; it is to send a native version to each network.
curl -X POST https://postwire.io/api/post \
-H "Authorization: Bearer $POSTWIRE_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"platforms": ["linkedin", "x"],
"text": "Your post",
"per_platform": {
"linkedin": { "text": "The LinkedIn version" },
"x": { "text": "The X version" }
}
}'
PostWire's /api/generate writes those per-platform versions for you from a single prompt, respecting
every limit in the table above. From an AI agent it is one MCP tool call.
Other pairs: X to LinkedIn · all combinations · which APIs need approval