twitter-to-bsky - crosspost from Twitter/X to Bluesky and Mastodon directly in the web browser

twitter-to-bsky is a userscript written for Tampermonkey or Violentmonkey running in desktop web browsers (Chrome/Firefox/Edge).

It allows to automatically crosspost to Bluesky and/or Mastodon when writing posts in the Twitter/X web application in a desktop browser.

While crossposting is generally considered a bad practice, in this case it makes sense, its purpose is to ease the transistion from X to Bluesky or Mastodon while there a still many users left that havn't followed on the new platform yet.

Crossposting obviously only makes sense for generic posts that e.g. link to a news article or blog post, but not for replies, mentions, DMs etc. which are Twitter/X-specific.

Features

twitter-to-bsky supports plain text posts, posts with one or several attached media files and posts containing a preview card, based on some entered URL. Note that Bluesky doesn't support videos/GIFs yet.

Setup

Install and activate either the Tampermonkey or Violentmonkey browser addon, then open this URL (the actual userscript) in the browser and allow the addon to install it as new userscript.

If you now (re-)load the Twitter/X page, it will be "enhanced" with the following new elements:

• a black cross button at the bottom of the navigation bar that allows to enter your Mastodon and/or Bluesky credentials in a small popup dialog (see details below).
• "Mastodon" and "Bluesky" checkboxes in the toolbar of the new post area (both inline and dialog). If a checkbox is checked, pressing the "Post" button will send the same post also to the corresponding platform.

Mastodon settings

• "Mastodon Instance URL" is the base URL of your Mastodon instance, e.g. "https://mastodon.social".
• "Mastodon Access Token" is an access token that you can create in the Mastodon web app via Settings -> Development -> New application.

Bluesky settings

• "Bluesky Handle" is your full handle (including ".bsky.social", if this applies).
• "Bluesky App Password" is not your main Bluesky password, but instead a so called "app password", in the Bluesky web app navigate to Settings -> Advanced -> App Passwords and create a new app password with a single click, then copy it and paste it into this field and save the changes.

Known limitation

While the script works fine with Chrome + Violentmonkey, the combination Firefox + Violentmonkey unfortunately has issues, about every other time the script is blocked due to CSP. This does not happen when using Tampermonkey, so for Firefox it's recommended to use Tampermonkey instead.

Screenshots

Twitter/X enhanced with crosspost elements

Settings dialog and system notifications (Windows 11)