# Thread splitter

Paste a long post and get it back as a thread: every part within the limit, split at paragraphs, then sentences, then words, and never inside a link or an emoji. Pick Bluesky and Mastodon, or type any limit.

Split a post at https://usepostify.com/tools/thread-splitter.

## Limits per part

- Bluesky: 300 characters
- Mastodon: 500 characters

## Run it from code

```bash
curl -s -X POST https://usepostify.com/api/tools/thread-split -H "Content-Type: application/json" -d '{"text":"Your long post…","limit":300,"numbering":true}'
```

## Questions

### How does the thread splitter decide where to break?

It fills each part as far as the limit allows, breaking at the largest boundary that fits: between paragraphs first, then between sentences, then between words. Only a single word longer than the whole limit is cut inside, and even then never through an emoji or an accented letter. A link is never cut; if one link is longer than the limit, it stays whole in its own part.

### How are characters counted?

As UTF-16 code units, the length a web browser reports for text and the same count Postify's composer and character counter use. Many emoji count as 2.

### What does numbering do?

It adds " 1/5", " 2/5" and so on to the end of each part. The room for those markers is taken out of each part's limit rather than added on top, so a numbered part still fits.

### Is there a limit on how many parts a thread can have?

Yes: 25, the most Postify publishes as one thread. Anything beyond that is folded into the last part rather than dropped, so nothing you wrote disappears; that last part is then over the limit and needs a trim.

### Can I split text from code?

Yes. Send the text and a network or a limit to https://usepostify.com/api/tools/thread-split. No API key is needed, and the answer is JSON, or Markdown with Accept: text/markdown.