Works, with rewrites

Cross-posting X to Facebook: what actually breaks

You can, but not by copying the text across: 3 things change between X and Facebook, starting with you have 1,720 characters you are not using. Below is exactly what breaks and what to do instead.

Side by side

XFacebook
Characters2802,000
Mediaoptionaloptional
Hashtags1-2 hashtags, zero is fine1-3 hashtags
Links in bodysuppress reachfine
Needs platform approvalyesyes

What changes, one by one

You have 1,720 characters you are not using

X caps at 280 characters, Facebook allows 2,000. Posting the short version verbatim wastes the room Facebook gives you to actually explain the thing.

The hashtag rules are not the same

X: 1-2 hashtags, zero is fine. Facebook: 1-3 hashtags. Carrying the tag block across is the single most obvious sign of an automated cross-post.

Facebook lets you put the link back in

X penalises links in the body, so posts written for it park the URL elsewhere. On Facebook links in the body are fine — putting it back is free reach.

Why copy-paste cross-posting underperforms

X is one hook and nothing else — opinionated, conversational, over in a breath. Facebook is warm and community-toned; 40-80 characters peaks engagement. 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.

Publish to both in one call

curl -X POST https://postwire.io/api/post \
  -H "Authorization: Bearer $POSTWIRE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "platforms": ["x", "facebook"],
    "text": "Your post",
    "per_platform": {
      "x": { "text": "The X version" },
      "facebook": { "text": "The Facebook 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.

Get an API key free →

Questions people actually ask

Can I cross-post from X to Facebook?
You can, but not by copying the text across: 3 things change between X and Facebook, starting with you have 1,720 characters you are not using. Below is exactly what breaks and what to do instead.
What is the character limit difference between X and Facebook?
X allows 280 characters and Facebook allows 2,000.
How do I post to X and Facebook at the same time?
With PostWire, one API call publishes to both: POST /api/post with platforms set to ["x","facebook"]. Or one MCP tool call from an AI agent.

Other pairs: Facebook to X · all combinations · which APIs need approval