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Quick Introduction To JSON

Items consist of JSON files with the .item.json file extension and sprites in PNG format, both inside the Items folder of your modpack. This page describes basic JSON Syntax that is used for making items (and other content in the future).


All item properties are set within the .item.json file, within a JSON Object (using curly brackets), like so:

    "a_property": "value",
    "another_setting": "another value",
    "a_yes_or_no_question": true,
    "my_favorite_number": 1337


Sometimes, it is nessesary to attach more than one value to a property. For this you should use a JSON Array (Square brackets). Multiple values are seperated by values, Like so:

    "shopping_list": ["Eggs","Milk","Bread","Apples"]


While not formally a part of the JSON Standard, Backpack Hero heavily relies on special values called Enums. Enums are basically text values, picked from a limited list of possible values. Imagine there was a weather property of type WeatherType, which allows for Sunny,Overcast,Rain,Storm. You could only use those four texts as the value of this property.

    "weather_today": "Sunny",
    "weather_tomorrow": "Overcast",
    "weather_next_week": ["Sunny","Rain","Overcast","Sunny","Storm","Overcast","Sunny"]
Enums are case in-sensitive. It is however strongly recommended to maintain cases, in case this changes.

Nesting Objects and Arrays

In JSON, values can't just contain text, numbers or true/false, but also more objects.
Objects, and Arrays can be nested many levels deep. This concept is heavily used for item effects. Notice the curly brackets inside the property:

    "my_car": {
        "color": "red",
        "max_speed": 160,
        "passengers" : ["Binary","Jas","Gangs"]
This also applies to values in Arrays. Notice the curly brackets seperated by commas inside the square brackets:
    "fruits": [