> For the complete documentation index, see [llms.txt](https://docs.startrail.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.startrail.io/metadata-schema/startrail-registry-srr/version-2.2.md).

# 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](https://eips.ethereum.org/EIPS/eip-721#specification) (You can search by "ERC721 Metadata JSON Schema")
* [OpenSea's metadata standards](https://docs.opensea.io/docs/metadata-standards#metadata-structure)

## Attributes

<mark style="color:red;">`*`</mark> is required.

<table><thead><tr><th width="236">Attribute</th><th width="335">Description</th><th width="204">data format</th><th width="374">Example</th></tr></thead><tbody><tr><td>$schema<mark style="color:red;">*</mark></td><td>IPFS URL to the schema json the given metadata follows. Fixed value for Metadata Version 2.2 in example value.</td><td>URL</td><td>ipfs://bafkreibebzcktpolubbklh73mxkxswkf3nagmvgq3tsnp33xsi6bbye5ay</td></tr><tr><td>chipUIDs</td><td>Array containing the list of the Chip UIDs of a physical artwork</td><td>Array of Strings</td><td>["1234567890abcdef"]</td></tr><tr><td>startbahnCertICTagUIDs</td><td>Define it as same as chipUIDs.</td><td>Array of Strings</td><td>["1234567890abcdef"]</td></tr><tr><td>title<mark style="color:red;">*</mark></td><td>Flexible language description object for title of the work.</td><td>Language Object (see at the bottom of the table)</td><td><p>{</p><p>"en": "A title",</p><p>"ja": "タイトル",</p><p>"zh": "一个标题"</p><p>}</p></td></tr><tr><td>note</td><td>Flexible language note object for title of the work.</td><td>Language Object (see at the bottom of the table)</td><td>{<br>"en": "The material is very fragile",<br>"zh": "该材料非常脆弱"<br>}</td></tr><tr><td>size</td><td>Object describing the size</td><td>object</td><td><p>{ "width": 200.0,</p><p>"height": 400.0,</p><p>"depth": 12.4,</p><p>"unit": "pixel",</p><p>"flexibleDescription":</p><p>{</p><p>"en": "flexibleDescription comes here",</p><p>"ja": "自由だーーー"</p><p>}</p><p>}</p></td></tr><tr><td>size.height</td><td>height dimension number.</td><td>number</td><td>10.5</td></tr><tr><td>size.width</td><td>width dimension number.</td><td>number</td><td>10.5</td></tr><tr><td>size.depth</td><td>depth dimension number.</td><td>number</td><td>10.5</td></tr><tr><td>size.unit</td><td>string specifying the unit of the dimensional numbers.</td><td>enumerated String with one of the following values. ["mm","cm","m","in","ft","pixel"]</td><td>mm</td></tr><tr><td>size.flexibleDescription</td><td>Alternative way to describe the size of the artwork, if the others dont apply.</td><td>Language Object (see at the bottom of the table)</td><td><p>{</p><p>"en": "flexibleDescription comes here",</p><p>"ja": "自由だーーー"</p><p>}</p></td></tr><tr><td>medium<mark style="color:red;">*</mark></td><td>Flexible language description object for the medium.</td><td>Language Object (see at the bottom of the table)</td><td><p>{</p><p>"en": "Oil on canvas",</p><p>"ja": "キャンバスに油彩",</p><p>"zh": "布面油画"</p><p>}</p></td></tr><tr><td>edition</td><td>Edition details</td><td>object</td><td><p>{</p><p>"uniqueness": "unique work",</p><p>"proofType": "ED",</p><p>"number": 1,</p><p>"totalNumber": 3,</p><p>"note": { "en": "some extra notes " }</p><p>}</p></td></tr><tr><td>edition.note</td><td>Note to add details to the Edition information</td><td>Language Object (see at the bottom of the table)</td><td><p>{</p><p>"en": "note comes here",</p><p>"ja": "自由だーーー"</p><p>}</p></td></tr><tr><td>edition.uniqueness</td><td>Uniqueness of artwork</td><td>enumerated String with one of the following values ["unique work", "non unique work", "unknown"]</td><td>unique work</td></tr><tr><td>edition.proofType</td><td><p>Proof type of edition: -ED Edition<br>-AP Artist Proof<br>-TP Trial Proof<br>-SP Special Proof<br>-HC Hors de Commerce<br>-Open Edition</p><p><br>Need to add it when the artwork is edition work.</p></td><td>enumerated String with one of the following values ["ED","AP","TP","SP","HC", "Open Edition"]</td><td>ED</td></tr><tr><td>edition.number</td><td>Edition number (out of total editions)</td><td>number (integer)</td><td>1</td></tr><tr><td>edition.totalNumber</td><td>Total number of editions</td><td>number (integer)</td><td>3</td></tr><tr><td>contractTerms</td><td>Object with contract details</td><td>Object</td><td><p>{</p><p>"royaltyRate": 15.7,</p><p>"fileURL": "https://startrail.io/whitepaper/startrail_wp_en_v1.1.pdf"</p><p>}</p></td></tr><tr><td>contractTerms.royaltyRate</td><td>Royalty rate percentage.</td><td>number (integer)</td><td>15.7</td></tr><tr><td>contractTerms.fileURL</td><td>URL where the contract terms file is stored</td><td>URL</td><td>https://startrail.io/whitepaper/startrail_wp_en_v1.1.pdf</td></tr><tr><td>thumbnailURL<mark style="color:red;">*</mark></td><td>URL where the artwork thumbnail is stored</td><td>URL</td><td><a href="https://storage.googleapis.com/opensea-prod.appspot.com/puffs/3.png">https://storage.googleapis.com/opensea-prod.appspot.com/puffs/3.png</a></td></tr><tr><td>isDigital</td><td>boolean indicator to specify that the work is a digital artwork.</td><td>boolean</td><td>true</td></tr><tr><td>digitalDataHash</td><td><mark style="color:red;">DEPRECATED</mark></td><td>-</td><td>-</td></tr><tr><td>digitalComponents</td><td><p><strong>ISSUE API USER should leave it UNDEFINED. You can specify these values outside metadata.</strong><br></p><p>Array of Digital file objects to specify digital components</p></td><td>Array of Digital File Objects (see at the bottom of the table)</td><td><p>[{</p><p>"hash": "sha256-247e4b904322a1dd0b148cd77e8627ec7d391251380880ab4621726ecb945ef5",</p><p>"category": "artwork"</p><p>}]</p></td></tr><tr><td>attachmentFiles</td><td><p><strong>ISSUE API USER should leave it UNDEFINED. You can specify these values outside metadata.</strong><br></p><p>Array of Digital file objects to specify attachment files.</p></td><td>Array of Digital File Objects (see at the bottom of the table)</td><td>[{ "hash": "sha256-247e4b904322a1dd0b148cd77e8627ec7d391251380880ab4621726ecb945ef5", "category": "certificate" }]</td></tr><tr><td>name<mark style="color:red;">*</mark></td><td>A field defined in ERC721. External interfaces including NFT marketplaces or wallets like OpenSea or MetaMask may show this field's value.<br><br>If <code>name</code> is not defined by client, it will be auto-filled with <code>title.en</code> value.</td><td>string</td><td>An example of title</td></tr><tr><td>description</td><td><p>A field defined in ERC721. External interfaces including NFT marketplaces or wallets like OpenSea or MetaMask may show this field's value.<br></p><p>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.</p></td><td>string</td><td>Description of example NFT</td></tr><tr><td>image<mark style="color:red;">*</mark></td><td><p>A field defined in ERC721. External interfaces including NFT marketplaces or wallets like OpenSea or MetaMask may show this field's value.<br></p><p>If <code>image</code> is not defined by client, it will be auto-filled with thumbnailURL value.</p></td><td>URL</td><td><a href="https://storage.googleapis.com/opensea-prod.appspot.com/puffs/3.png">https://storage.googleapis.com/opensea-prod.appspot.com/puffs/3.png</a></td></tr><tr><td>external_url</td><td><p>External reference URL used for OpenSea.</p><p>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 .</p></td><td>URL</td><td><a href="https://openseacreatures.io/3">https://openseacreatures.io/3</a></td></tr><tr><td>yearOfCreation<mark style="color:red;">*</mark></td><td>Flexible language description object for the year of the creation</td><td>Language Object (see at the bottom of the table)</td><td><p>{</p><p>"en": "around 2010-2020",</p><p>"ja": "2010年から2020年頃"</p><p>}</p></td></tr><tr><td>attributes</td><td>OpenSea customizable filterable attributes. Check <a href="https://docs.opensea.io/docs/metadata-standards#attributes">https://docs.opensea.io/docs/metadata-standards#attributes</a></td><td>Array of Attributes Object (see at the bottom of the table)</td><td><p>[{</p><p>"trait_type": "Mouth",</p><p>"value": "Surprised"</p><p>}]</p></td></tr></tbody></table>

### Object

<table><thead><tr><th width="255">Attribute</th><th width="464">Description</th><th width="204">data format</th><th width="374">Example</th></tr></thead><tbody><tr><td>&#x3C;Language Object></td><td>An object specifying multiple supported languages. The property names are two letter letter language codes from BCP-47, such as en or ja.</td><td>Each property name: 2 char string from BCP-47, value: string</td><td><p>{</p><p>"en": "A title",</p><p>"ja": "タイトル",</p><p>"zh": "一个标题"</p><p>}</p></td></tr><tr><td>&#x3C;Digital File Object></td><td>An object providing details of digital files.</td><td>Object</td><td>{ "hash": "sha256-247e4b904322a1dd0b148cd77e8627ec7d391251380880ab4621726ecb945ef5", "category": "artwork", "URL":"https://some.url.com/file", "name":"filename.jpg" }</td></tr><tr><td>&#x3C;Digital File Object>.hash</td><td><p>ISSUE API USER should leave it UNDEFINED</p><p>sha256 Hash Hex String of the file.</p></td><td>sha256 Hash Hex String</td><td>sha256-f63238ce3b8c4f8a99fb453d716d5451f75508c2e403a58af0412014187e7a61</td></tr><tr><td>&#x3C;Digital File Object>.category</td><td>String describing the category of the file.</td><td>String to describe the category. Supported values in Startrail PORT: ”certificate”, “for_authenticity”,”artwork”,”installation”</td><td>artwork</td></tr><tr><td>&#x3C;Digital File Object>.URL</td><td>url where the file can be accessed</td><td>URL</td><td></td></tr><tr><td>&#x3C;Digital File Object>.name</td><td>name of the file</td><td>string</td><td></td></tr><tr><td>&#x3C;Attributes Object></td><td>OpenSea customizable filterable attributes. Check <a href="https://docs.opensea.io/docs/metadata-standards#attributes">https://docs.opensea.io/docs/metadata-standards#attributes</a></td><td>Array of Object</td><td><p>{</p><p>"trait_type": "Mouth",</p><p>"value": "Surprised"</p><p>}</p></td></tr><tr><td>&#x3C;Attributes Object>.trait_type</td><td>Check <a href="https://docs.opensea.io/docs/metadata-standards#attributes">https://docs.opensea.io/docs/metadata-standards#attributes</a></td><td>string</td><td>Mouth</td></tr><tr><td>&#x3C;Attributes Object>.value</td><td>Check <a href="https://docs.opensea.io/docs/metadata-standards#attributes">https://docs.opensea.io/docs/metadata-standards#attributes</a></td><td>string</td><td>Surprised</td></tr></tbody></table>

### Changes From the Previous Version

1. Change of `$schema`into IPFS URL
2. removal of of `$schemaIntegrity`
3. Addition of a new field `attributes`

## Complete Example

```json
{
  "$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"
}
```


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