bluesky.text.max_graphemes - letmepost.dev

What it checks

countGraphemes(text) <= 300. The grapheme counter uses Unicode segmentation, so 👨‍👩‍👧‍👦 is one grapheme, not seven codepoints.

Why 300

The cap matches Bluesky’s app.bsky.feed.post schema constant, which is itself defined in graphemes — not bytes, not codepoints, not UTF-16 codeunits. We use the same counter the platform uses, so what passes preflight passes upstream.

Failure response

{
  "error": {
    "code": "preflight_failed",
    "rule": "bluesky.text.max_graphemes",
    "platform": "bluesky",
    "message": "Post text is 312 graphemes; Bluesky allows at most 300.",
    "remediation": "Shorten the post to 300 graphemes or fewer."
  }
}

Remediation

Trim the post. If you’re truncating programmatically, use a grapheme-aware splitter. JavaScript’s string.length counts UTF-16 codeunits and will under-count emoji; use Intl.Segmenter or graphemer.

import Graphemer from "graphemer";
const g = new Graphemer();
const truncated = g.splitGraphemes(text).slice(0, 300).join("");