FediThready Documentation

FediThready splits long text into Mastodon-friendly chunks so you can post a thread without hitting the character limit. Everything runs in your browser — no account required to split and copy text, and no data ever leaves your device except when you choose to post directly to Mastodon.

1. Type (or paste) your long text into the Write Your Text area.
2. Watch the Preview panel on the right update in real time as FediThready splits your text into post-sized chunks.
3. Adjust settings as needed (see Settings below).
4. Either:
   • Click Copy on each chunk and paste it into your Mastodon app one post at a time, or
   • Connect to Mastodon and post the whole thread in one click.

FediThready will automatically split your text at sentence boundaries when possible, and at word boundaries otherwise. If you want to control exactly where a split happens, insert a divider line on its own line:

• Three or more hyphens: ---
• Three or more underscores: ___
• Three or more asterisks: ***

Any of these force a split at that point, regardless of character count. The divider itself does not appear in the posted text.

Example:

This is the first post in my thread.
---
This will be a separate post even though both fit in 500 characters.

Type a content warning into the optional content warning field above the text area. It applies to every post in the thread. The content warning counts toward the character limit on Mastodon, so FediThready subtracts its length when calculating how much text fits in each chunk.

When replying to a post that has a content warning, FediThready copies that warning into the field automatically (if the field is currently empty) so your reply inherits the same warning.

Connecting lets you post your entire thread directly from FediThready with one click. FediThready uses OAuth 2.0 — your password is never entered here.

1. Click the green Log in to post button.
2. Enter your Mastodon instance domain — the domain you use to access your account. For example:
   • If your username is @alice@mastodon.social, enter mastodon.social.
   • If your username is @alice@example.com but your profile lives at social.example.com/alice, enter social.example.com.
3. Click Authorize. You will be redirected to your instance to approve access.
4. After approving, you are returned to FediThready and the button changes to Post Thread.
5. Click Post Thread to publish. FediThready posts each chunk as a reply to the previous one, forming a thread automatically.

To disconnect, click the Disconnect button. Your access token is removed from the browser; you can reconnect at any time.

Note: Posting requires FediThready to be served over HTTP or HTTPS (i.e. loaded from a web server). If you open the file directly in your browser (file://), the Copy workflow still works but posting is disabled for security reasons. Visit fedithready.app to use posting.

Use the Visibility dropdown in the Preview panel to choose who can see your posts:

When replying to a post, FediThready automatically matches the visibility of the original post (with the exception of Followers only — if the original is followers-only, FediThready leaves your visibility at whatever you had selected, since you may not follow each other). Your previous visibility setting is restored when you clear the reply-to URL.

Direct visibility requirement: If you select Direct, your first chunk must contain at least one @username@instance mention and the Include usernames in replies checkbox must be enabled. Otherwise FediThready will alert you before posting.

1. Log in to Mastodon (see Connecting to Mastodon).
2. Click Reply to post… in the Preview panel to expand the reply section.
3. Paste the URL of the post you want to reply to.
4. FediThready looks up the post on your instance and shows a preview of it, including the author, content, and any attached images.
5. Click Post Thread — the first chunk of your thread is sent as a reply to that post, and subsequent chunks chain off one another.

The reply-to URL is saved between sessions so you can continue a draft later. Click the × button next to the URL field, or click Clear Current Text, to remove it.

FediThready lets you attach images to specific posts in your thread by dragging them into the browser window.

• Reorder chunks: Use manual dividers (---) to control exactly where splits fall, then move text around until the preview looks the way you want.
• Long URLs: Mastodon counts URLs as a fixed number of characters (usually 23) regardless of their actual length. FediThready does not currently apply this shortening, so chunks containing long URLs may appear slightly over the limit in the character count but will post fine.
• Emoji: Mastodon counts each emoji as one character. FediThready does the same, so character counts should match what your Mastodon client shows.
• Drafts: FediThready saves your text, content warning, and reply-to URL in your browser's local storage. Closing the tab and coming back later restores your draft automatically.
• Without an account: Every feature except posting works without logging in. Use the Copy buttons on each chunk and paste into your Mastodon app manually.

If something is not working, you have a question, or you have a suggestion:

• File an issue on GitHub: github.com/masukomi/fedithready/issues/new
• Drop the creator a message on Mastodon: @masukomi@connectified.com

The source code can be found at https://github.com/masukomi/fedithready/ and is distributed under the MIT license.

Historically this started out as someone's experiment with early LLM coding tools, was manually reworked by a human, and has since been expanded dramatically via Claude.

Every attempt has been made to make sure that this code doesn't and can't violate your privacy.

This is a useful little side project that should never be relied on for anything that could cost you money or security if it goes wrong. If you're not comfortable using things generated by an LLM, then don't use this.