Addon Manifest

Some parts of this documentation may be missing or outdated. You can help improving this page.
Do not hesitate to ask questions regarding this by using the provided channels.

Addons are located inside the addons folder. Each addon is inside its own folder as well. In order to tell the addon loader how the addon plans to work, addons use a standard addon.json file located at the root of the addon’s folder.

name (string, required)

The name of the addon. Must be Sentence case.
It needs to be relatively short and consistent with other addon’s names.
Use nouns instead of verbs (for example, Customizable new sprite position instead of Change new sprite position).

description (string, required)

The description of the addons. Must end with a dot.

Use standard grammar for referring to parts of the Scratch website or editor:

Pages on the website:

  • project page
  • editor
  • (user) profile
  • studio page
  • forums
  • (forum) topic
  • (forum) post
  • (Scratch) 2.0/3.0-styled page (a page which looks like Scratch 2.0/3.0, is a part of scratchr2/scratch-www)

Scratch UI elements:

  • (website) navigation bar (only use when talking about the website)
  • (editor) menu bar (only use when talking about the editor)
  • sprite pane (the list of sprites below the stage)
  • costume editor (not paint editor), list of costumes
  • list of sounds, costume/sound list (for features that work with both costumes and sounds)
  • costume/sound (not asset)
  • block category
  • block category menu
  • block palette
  • code area (not workspace - Code tab excluding the block palette)
  • block dropdown (a dropdown menu opened by clicking a block input)
  • block context menu (a menu opened by right clicking a block)
  • script (not stack of blocks)
  • extension
  • comment (on the website/in the code area)

Locations of added UI elements:

  • in (not on) the navigation bar
  • on (not in) the forums
  • on (not in) the stage
  • above the stage (in the editor/on the project page)
  • next to the green flag
  • next to the Remix button

Common words:

  • customizable

tags (array, required)

Tags are used for filtering and badges on the Scratch Addons settings page.

Required factual tags

Addons must have one of these tags. No less than one, no more than one.

Tag name Used by settings page Description
community ✔️ Scratch website features
editor ✔️ Scratch editor features
popup ✔️ Extension popup features

Optional factual tags

Addon authors can usually determine these tags themselves.

Tag name Used by settings page Description
theme ✔️ Addons that should be listed in the "themes" category. Tags community or editor are still required.
easterEgg ✔️ Addons with this tag are visible in the settings page while disabled only after typing the Konami code.
codeEditor ✔️ Addons that mainly affect the Code tab of the editor.
costumeEditor ✔️ Addons that mainly affect the Backdrops/Costumes tab of the editor.
projectPlayer ✔️ Addons that affect the project player in both the website and editor, or that add UI elements above the stage.
editorMenuBar Addons that add UI elements to the editor's menu bar.
projectPage ✔️ Addons that affect project pages on the website.
profiles ✔️ Addons that affect profile pages on the website.
forums ✔️ Addons that affect the Scratch Forums.
studios Addons that affect studio pages on the website.
comments Addons that affect comments on the website, inside project pages, profiles and studios.

Optional subjective tags

Addon authors shouldn’t add these tags themselves.
Whether to add any of these tags will be discussed before merging the addon to the repository.

Tag name Used by settings page Description
recommended ✔️ Addons that add highly requested, removed, or obvious missing features.
beta ✔️ Addons that haven't been deeply tested, may break in the future or are known to not work properly.
danger ✔️ Addons that users shouldn't enable without paying close attention.

permissions (array)

You can specify permissions by providing a permissions array.
Possible items: "notifications", "badge", "clipboardWrite".

persistentScripts (array)

You can add persistent scripts by providing a persistentScripts array conformed of JS files (e.g. ["example.js"]).

userscripts and userstyles (array)

Declaring userscripts and userstyles is very similar. Unlike persistent scripts, this is an array of objects, not strings.
Each object must specify the url to the userscript/userstyle through the "url" property, and provide an array of URL matches. If any of these patterns match, the userscript/userstyle is injected.

matches (array)

Matches that allow the userscript/userstyle to run on. Values can be a URL match pattern, or projects, projectEmbeds, studios, profiles, topics, newPostScreens, editingScreens, forums, scratchWWWNoProject.

  "userscripts": [
      "url": "userscript.js",
      "matches": ["*"]
      "url": "second_userscript.js",
      "matches": ["", "*"]

settingMatch (object)

You can provide a settingMatch object that will result in your userscript/userstyle only running if the specified option is set to the specified value.

  "userstyles": [
      "url": "signature.css",
      "matches": ["*"],
      "settingMatch": {
        "id": "signature",
        "value": true

runAtComplete (boolean, userscripts only)

Specifies whether the userscript should run after the page has loaded (after the window load event). If unspecified, true is assumed.
If set to false, the userscript is only guaranteed to run after the <head> element of the document has loaded.

settings (object)

Settings allow the addon’s users to specify settings in Scratch Addons' settings panel. Inside your persistent scripts and userscripts, you can then access those settings with the addon.settings API.
Specify a settings property and provide an array of option objects.

The properties of the object are as follows. All properties are required.

  • "name": the user-visible text for the option.
  • "id": an identifier to get the user-specified value from your code.
  • "type": either "boolean" (a checkbox), "positive_integer" (an input box that only allows 0 and above), "string" (up to 100 chars),"color" (a browser color input that returns a hex code) or "select" (see "potential_values").
  • "default": the default value for the option. A boolean, string, or number, depending on the specified type.
  • "potentialValues": for "select" type only. Array of objects, with properties "id", the value received from addon.settings.get(), and "name", the user-visible option text.
  • "allowTransparency": for "color" type only. Boolean.
  "settings": [
      "name": "Send notifications",
      "id": "send_notifications",
      "type": "boolean",
      "default": false
      "name": "Notification close delay in seconds",
      "id": "close_delay",
      "type": "positive_integer",
      "default": 5

credits (array)

You can provide a credits array of objects. This attribution is shown in the extension settings.
These objects must have a "name" attribute set to a string, and they can have a "link" attribute with a URL value.

  "credits": [
      "name": "Maximouse",
      "link": ""

enabledByDefault (boolean)

You can provide the enabledByDefault property and set it to true to specify if the addon should be enabled by default. Its default value is false.
Keep in mind, few addons will be enabled by default. If you want your addon to be enabled by default, please open a discussion issue.

info (array)

An array of additional information (e.g. warnings, notices) about the addon. Each item of the array is an object consisting of type (string) -either warning or notice - text (string) - the text to be displayed - and id (string) - the id of the information. Example:

  "info": [
      "type": "notice",
      "text": "Example notice.",
      "id": "exmapleID"
      "type": "warning",
      "text": "Example warning.",
      "id": "exmapleID"

presets (array)

An array of presets for the addon. Each item in the presets array should be an object consisting of name (string), id(string), description (string) and values (object). The keys in the values object should the addon settings ids, and the values should be the values to set the setting with the id of the key to.


  "presets": [	
      "name": "preset 1",	
      "id": "preset1",	
      "desctiption": "the first preset",	
      "values": {	
        "boolean_setting": true,	
        "string_setting": "This is a string setting",	
        "integer_setting": 180	

libraries (array)

An array of libraries that the addon uses.

When added, creates a new popup tab in the browser popup. Example:

  "popup": {
    "icon": "../../images/icons/envelope.svg",
    "name": "Messaging",
    "fullscreen": true

dynamicDisable (boolean)

Indicates whether the addon’s scripts should be considered disabled when disabled as the page is running. Defaults to false.

dynamicEnable (boolean)

Indicates whether the addon’s scripts should be considered enabled when enabled as the page is running. Defaults to false.

injectAsStyleElt (boolean)

Indicates whether the addon’s userstyles should be injected as style elements rather than link elements. Defaults to false.

updateUserstylesOnSettingsChange (boolean)

Indicates whether the addon’s userstyles should be removed and rematched to the new settings. Defaults to false.

versionAdded (string)

The version the addon was added. If the value is the same as the current version of the extension, the addon will get the new tag.

Last updated at 16 August 2021 by Pufferfish101007 on commit aa2f1d0. Improve this page.