facebook.text.max_graphemes - letmepost.dev

What it checks

countGraphemes(text) <= 63_206.

Why 63,206

Facebook’s hard server-side cap on a Page post is 63,206 characters — an oddly specific value chosen by Meta. Above it, Graph API rejects with code 100. We pre-check against graphemes; since Facebook counts UTF-16 codeunits but graphemes ≤ codeunits, we never over-permit a payload that would 100 upstream.

Failure response

{
  "error": {
    "code": "preflight_failed",
    "rule": "facebook.text.max_graphemes",
    "platform": "facebook",
    "message": "Post text exceeds Facebook's 63206-character cap."
  }
}

Remediation

If you’re hitting this, the post is probably better as a Note or a link to a longer-form surface. Trim to under 63,206 characters.