This page describes the different ways of defining the collection metadata. This information is used to create the items and inscribe them on-chain during the inscription process.

Programmatically

The recommended way of defining the collection metadata in a dynamic environment is using Typescript/Javascript.

Example programmatic collection metadata

import { Types } from '@handcash/handcash-connect';

const collectionMetadata: Types.CollectionDefinition = {
  name: 'Example collection',
  description: 'A collection with example items',
  mediaDetails: {
    image: {
      url: 'https://res.cloudinary.com/handcash-iae/image/upload/v1685141160/round-handcash-logo_cj47fp_xnteyo_oy3nbd.png',
      contentType: 'image/png',
    },
  },
};

const collectionItems: Types.CreateItemMetadata[] = [
  {
    name: 'An example item',
    rarity: 'Common',
    attributes: [
      {
        name: 'Edition',
        value: 'First',
        displayType: 'string',
      },
    ],
    mediaDetails: {
      image: {
        url: 'https://res.cloudinary.com/handcash-iae/image/upload/v1702398906/items/da2qv0oqma0hs3gqevg7.webp',
        imageHighResUrl: 'https://res.cloudinary.com/handcash-iae/image/upload/v1697465892/items/gh7tsn11svhx7z943znv.png',
        contentType: 'image/png',
      },
    },
    color: '#B19334',
    quantity: 5,
  },
];

Collection Types

Here's an example of collection metadata:

{
  "name": "Example collection",
  "description": "A collection with example items",
  "mediaDetails": {
    "image": {
      "url": "https://handcash.io/asset/000012.png",
      "contentType": "image/png"
    }
  }
}

Property	Description
`name`	Collection name.
`description`	Short description about this collection.
`mediaDetails`	An image to represent this collection in the wallet and in the market.

Items

Here's an example of a collection item metadata:

{
  "name": "An example item",
  "rarity": "Common",
  "color": "#B19334",
  "quantity": 5,
  "mediaDetails": {
    "image": {
         "url": "https://handcash.io/item/188272.webp",
         "imageHighResUrl": "https://handcash.io/item/188272.png",
         "contentType": "image/webp"
    }
  },
  "attributes": [
    {
      "name": "Edition",
      "value": "First",
      "displayType": "string"
    }
  ],
  "externalId": "0000012344"
}

This is how each of these properties is used:

Property	Description
`name`	Item name
`rarity`	Should be one of [`"Common"`, `"Uncommon"`, `"Rare"`, `"Epic"`, `"Mythic"`].
`color`	Hex color to represent this item. (Optional).
`quantity`	Total quantity of this item.
`mediaDetails`	Assets to represent this item. (see below)
`attributes`	These are the attributes for the item, which will show up on the HandCash for the item. (see below)
`user`	The user id to create the item to (Optional).
`externalId`	An id that links the item to your internal database, this is a common way to search inventories later on (Optional)
`groupingValue`	A unique identifier to distinguish items with the same name but different characteristics. For example, a Pokémon card named Charizard could belong to different editions or have a holographic version. This field helps to differentiate between such variations. If not provided it will be derived based on the name using a hash function, for example it will look like this`90c08fbd22f8f73dfd89ed592276426d` (Optional)

Attributes

Each item can be described using the following properties:

Property	Description
`name`	The attribute name
`value`	The attribute value
`displayType`	The way this value should be represented. (see below)

Display types

These are the supported display types to represent attributes:

string: "fire"
number: 4
date: 23/05/2023
boostPercentage: +7%
boostNumber: +10

String

{
  "name": "Element",
  "displayType": "string", 
  "value": "Fire"
}

Number

{
  "name": "Attack",
  "displayType": "number", 
  "value": 8
}

Date

Pass in a unix timestamp (seconds) as the value.

{
  "name": "Birthday",
  "displayType": "string", 
  "value": 1688280400
}

Boost Percentage

{
  "name": "Element",
  "displayType": "string", 
  "value": "Fire"
}

Boost Number

{
  "name": "Attack increase",
  "displayType": "boostNumber", 
  "value": 3
}

Media details

The media details define the different assets available to represent the item:

Property	Description
`image`	The main image used to represent the item in the wallet and in the market
`multimedia`	Complementary asset to represent this item (3D files, audio files, etc...)

{
  "image": {
    "url": "https://handcash.io/item/188272.webp",
    "imageHighResUrl": "https://handcash.io/item/188272.png",
    "contentType": "image/webp"
  },
  "multimedia": {
    "url": "https://handcash.io/asset/3dImage.glb",
    "contentType": "application/glb"
  }
}

Property	Description
`url`	An image url to represent an item that is put on the blockchain, 50kb size limit
`imageHighResUrl`	A high resolution image of an item that is not put on chain but is used to display the item
`contentType`	One of [`"image/png"`, `"image/jpg"`, `"image/gif"`, `"text/html"`, `"audio/mpeg"`, `"application/fbx"`, `"application/glb"`]

Expected image sizes

image.url max size is 50kb and image.imageHighResUrl has no limit.

image.url will be put on chain and should be a lower resolution image, image.imageHighResUrl will be used to display the item in the inventory and market. It should follow the guidelines below for best results. Please reach out to Handcash Support or Sales with any questions or if you would like to put larger files on chain.

Context	Aspect ratio	Optimal resolution
Collection	2:1	600x300
Collection items	From 1:1 to 2:3	From 728:728 to 2048:2048