Version 2.2

External References

These links are helpful to understand what attributes are widely referenced by external applications such as wallets and NFT marketplaces.

• ERC721 specification (You can search by "ERC721 Metadata JSON Schema")

• OpenSea's metadata standards

Attributes

* is required.

Attribute	Description	data format	Example
$schema*	IPFS URL to the schema json the given metadata follows. Fixed value for Metadata Version 2.2 in example value.	URL	ipfs://bafkreibebzcktpolubbklh73mxkxswkf3nagmvgq3tsnp33xsi6bbye5ay
chipUIDs	Array containing the list of the Chip UIDs of a physical artwork	Array of Strings	["1234567890abcdef"]
startbahnCertICTagUIDs	Define it as same as chipUIDs.	Array of Strings	["1234567890abcdef"]
title*	Flexible language description object for title of the work.	Language Object (see at the bottom of the table)	{ "en": "A title", "ja": "タイトル", "zh": "一个标题" }
note	Flexible language note object for title of the work.	Language Object (see at the bottom of the table)	{ "en": "The material is very fragile", "zh": "该材料非常脆弱" }
size	Object describing the size	object	{ "width": 200.0, "height": 400.0, "depth": 12.4, "unit": "pixel", "flexibleDescription": { "en": "flexibleDescription comes here", "ja": "自由だーーー" } }
size.height	height dimension number.	number	10.5
size.width	width dimension number.	number	10.5
size.depth	depth dimension number.	number	10.5
size.unit	string specifying the unit of the dimensional numbers.	enumerated String with one of the following values. ["mm","cm","m","in","ft","pixel"]	mm
size.flexibleDescription	Alternative way to describe the size of the artwork, if the others dont apply.	Language Object (see at the bottom of the table)	{ "en": "flexibleDescription comes here", "ja": "自由だーーー" }
medium*	Flexible language description object for the medium.	Language Object (see at the bottom of the table)	{ "en": "Oil on canvas", "ja": "キャンバスに油彩", "zh": "布面油画" }
edition	Edition details	object	{ "uniqueness": "unique work", "proofType": "ED", "number": 1, "totalNumber": 3, "note": { "en": "some extra notes " } }
edition.note	Note to add details to the Edition information	Language Object (see at the bottom of the table)	{ "en": "note comes here", "ja": "自由だーーー" }
edition.uniqueness	Uniqueness of artwork	enumerated String with one of the following values ["unique work", "non unique work", "unknown"]	unique work
edition.proofType	Proof type of edition: -ED Edition -AP Artist Proof -TP Trial Proof -SP Special Proof -HC Hors de Commerce -Open Edition Need to add it when the artwork is edition work.	enumerated String with one of the following values ["ED","AP","TP","SP","HC", "Open Edition"]	ED
edition.number	Edition number (out of total editions)	number (integer)	1
edition.totalNumber	Total number of editions	number (integer)	3
contractTerms	Object with contract details	Object	{ "royaltyRate": 15.7, "fileURL": "https://startrail.io/whitepaper/startrail_wp_en_v1.1.pdf" }
contractTerms.royaltyRate	Royalty rate percentage.	number (integer)	15.7
contractTerms.fileURL	URL where the contract terms file is stored	URL	https://startrail.io/whitepaper/startrail_wp_en_v1.1.pdf
thumbnailURL*	URL where the artwork thumbnail is stored	URL	https://storage.googleapis.com/opensea-prod.appspot.com/puffs/3.png
isDigital	boolean indicator to specify that the work is a digital artwork.	boolean	true
digitalDataHash	DEPRECATED	-	-
digitalComponents	ISSUE API USER should leave it UNDEFINED. You can specify these values outside metadata. Array of Digital file objects to specify digital components	Array of Digital File Objects (see at the bottom of the table)	[{ "hash": "sha256-247e4b904322a1dd0b148cd77e8627ec7d391251380880ab4621726ecb945ef5", "category": "artwork" }]
attachmentFiles	ISSUE API USER should leave it UNDEFINED. You can specify these values outside metadata. Array of Digital file objects to specify attachment files.	Array of Digital File Objects (see at the bottom of the table)	[{ "hash": "sha256-247e4b904322a1dd0b148cd77e8627ec7d391251380880ab4621726ecb945ef5", "category": "certificate" }]
name*	A field defined in ERC721. External interfaces including NFT marketplaces or wallets like OpenSea or MetaMask may show this field's value. If name is not defined by client, it will be auto-filled with title.en value.	string	An example of title
description	A field defined in ERC721. External interfaces including NFT marketplaces or wallets like OpenSea or MetaMask may show this field's value. If description is not designated, it will be auto-filled with other fields such as size, medium, edition, issuer name, artist name, note, yearOfCreation, contractTerms.fileURL.	string	Description of example NFT
image*	A field defined in ERC721. External interfaces including NFT marketplaces or wallets like OpenSea or MetaMask may show this field's value. If image is not defined by client, it will be auto-filled with thumbnailURL value.	URL	https://storage.googleapis.com/opensea-prod.appspot.com/puffs/3.png
external_url	External reference URL used for OpenSea. if metadata.external_url is designated, it can have different URL from payload.externalUrls . if metadata.external_url is NOT designated, it will have the first URL from payload.externalUrls .	URL	https://openseacreatures.io/3
yearOfCreation*	Flexible language description object for the year of the creation	Language Object (see at the bottom of the table)	{ "en": "around 2010-2020", "ja": "2010年から2020年頃" }
attributes	OpenSea customizable filterable attributes. Check https://docs.opensea.io/docs/metadata-standards#attributes	Array of Attributes Object (see at the bottom of the table)	[{ "trait_type": "Mouth", "value": "Surprised" }]

Object

Attribute	Description	data format	Example
<Language Object>	An object specifying multiple supported languages. The property names are two letter letter language codes from BCP-47, such as en or ja.	Each property name: 2 char string from BCP-47, value: string	{ "en": "A title", "ja": "タイトル", "zh": "一个标题" }
<Digital File Object>	An object providing details of digital files.	Object	{ "hash": "sha256-247e4b904322a1dd0b148cd77e8627ec7d391251380880ab4621726ecb945ef5", "category": "artwork", "URL":"https://some.url.com/file", "name":"filename.jpg" }
<Digital File Object>.hash	ISSUE API USER should leave it UNDEFINED sha256 Hash Hex String of the file.	sha256 Hash Hex String	sha256-f63238ce3b8c4f8a99fb453d716d5451f75508c2e403a58af0412014187e7a61
<Digital File Object>.category	String describing the category of the file.	String to describe the category. Supported values in Startrail PORT: ”certificate”, “for_authenticity”,”artwork”,”installation”	artwork
<Digital File Object>.URL	url where the file can be accessed	URL
<Digital File Object>.name	name of the file	string
<Attributes Object>	OpenSea customizable filterable attributes. Check https://docs.opensea.io/docs/metadata-standards#attributes	Array of Object	{ "trait_type": "Mouth", "value": "Surprised" }
<Attributes Object>.trait_type	Check https://docs.opensea.io/docs/metadata-standards#attributes	string	Mouth
<Attributes Object>.value	Check https://docs.opensea.io/docs/metadata-standards#attributes	string	Surprised

Changes From the Previous Version

1. Change of $schemainto IPFS URL

2. removal of of $schemaIntegrity

3. Addition of a new field attributes

Complete Example

{
  "$schema": "ipfs://bafkreibebzcktpolubbklh73mxkxswkf3nagmvgq3tsnp33xsi6bbye5ay",
  "startbahnCertICTagUIDs": [
    "1234567890abcdef"
  ],
  "chipUIDs": [
    "1234567890abcdef"
  ],
  "title": {
    "en": "A title",
    "ja": "タイトル",
    "zh": "一个标题"
  },
  "size": {
    "width": 200.0,
    "height": 400.0,
    "depth": 12.4,
    "unit": "pixel",
    "flexibleDescription": {
      "en": "flexibleDescription comes here",
      "ja": "自由だーーー"
    }
  },
  "attributes": [
    {
      "trait_type": "Mouth",
      "value": "Surprised"
    }
  ],
  "medium": {
    "en": "Oil on canvas",
    "ja": "キャンバスに油彩",
    "zh": "布面油画"
  },
  "edition": {
    "uniqueness": "unique work",
    "proofType": "ED",
    "number": 1,
    "totalNumber": 3,
    "note": {
      "en": "some extra notes in 1 or more languages"
    }
  },
  "contractTerms": {
    "royaltyRate": 15.7,
    "fileURL": "https://startrail.io/whitepaper/startrail_wp_en_v1.1.pdf"
  },
  "note": {
    "en": "note",
    "zh": "注意"
  },
  "thumbnailURL": "https://storage.googleapis.com/opensea-prod.appspot.com/puffs/3.png",
  "yearOfCreation": {
    "en": "around 2010-2020",
    "ja": "2010年から2020年頃"
  },
  "isDigital": true,
  "digitalDataHash": "sha256-247e4b904322a1dd0b148cd77e8627ec7d391251380880ab4621726ecb945ef5",
  "digitalComponents": [{
    "hash": "sha256-247e4b904322a1dd0b148cd77e8627ec7d391251380880ab4621726ecb945ef5",
    "category": "artwork"
  }],
  "attachmentFiles": [{
    "hash": "sha256-247e4b904322a1dd0b148cd77e8627ec7d391251380880ab4621726ecb945ef5",
    "category": "artwork"
  }],
  "name": "some nft name",
  "description": "some nft description",
  "image": "https://storage.googleapis.com/opensea-prod.appspot.com/puffs/3.png",
  "external_url": "https://openseacreatures.io/3"
}