Extension that adds a "Yeah!" button to Twitter. Essentially, it's a public Like button. It doesn't send spammy images into replies, instead it saves your Yeahs into a shared database. Everyone can see who Yeahed a tweet, and what tweets person Yeahed.
This extension supports both new Twitter and OldTwitter!

Chrome, Edge, Opera, Brave, Vivaldi, etc:

Firefox, Waterfox, LibreWolf, Floorp, etc:

Userscript (Tampermonkey, Greasemonkey, Violentmonkey, etc):

1. Go to Releases page.
2. Download chrome.zip if you're on Chromium based browsers (Chrome, Edge, Opera, Brave, etc.) or firefox.zip if you're on Firefox.

• Unpack file anywhere
• Go to chrome://extensions
• Turn on Developer mode
• Press "Load unpacked" and select folder with extension

• Go to about:debugging#/runtime/this-firefox
• Press "Load Temporary Add-on" and select zip file you downloaded
• Installing it this way will remove extension after browser restart, see below for permanent installation

• Go to about:config
• Set xpinstall.signatures.required to false
• Go to about:addons
• Press "Install Add-on From File" and select zip file you downloaded

If you wish to implement Yeah! button in your Twitter mod, you can use this API.
Base URL: https://yeah.dimden.dev
All requests use POST method.
All requests require Content-Type: application/json.

Returns { public_token: String, private_token: String }.
You need to make user tweet yeah-xxxxxxxx where xxxxxxxx is public token.

Requires body: { public_token: String, private_token: String, tweet: Tweet }.
Tweet is object of this format. Must also include user object inside with id_str.
Will reply with success if everything went correctly. After that you can save private_token somewhere to use in other requests.

Requires body: { post_ids: String, key: private_token }.
post_ids is string of tweet IDs separated by comma. Max 100 tweets per request.
Will return [ { post_id: String, count: Number, yeahed: Boolean }, ... ].

Requires body: { post_id: String, key: private_token }.
Will reply with done if everything went fine.

Requires body: { post_id: String, key: private_token }.
Will reply with done if everything went fine.

Requires body: { post_id: String, key: private_token, page: Number }.
page starts with 1.
Will return an array with user ids.

Requires body: { user_id: String, key: private_token, page: Number }.
page starts with 1.
Will return an array with tweet ids.

Requires body: { user_id: String, key: private_token }.
Will return { count: Number }.