> For the complete documentation index, see [llms.txt](https://myty.gitbook.io/products/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://myty.gitbook.io/products/kit/getting-started/2.-trait-mapping/new-field-token-id.md).

# New Field: Token ID

## Trait Mapper File Format Has Been Updated!

* A new field `tokenId` is added
  * Since NFT’s token id can be extremely large enough (exceeding `2^64`), we are introducing a new field: `tokenId` with **string** data type
  * It is required to insert at least one of `id`, `tokenId,` for each item. When both fields are included in a single item, `id` is ignored and `tokenId` is used
* The original field `id` still works
  * `id` can be used rather than `tokenId`. The new version of MYTY Kit is compatible with previous Trait Mapper file and asset bundles.
  * The field `id` may be deprecated in the future, so it is highly recommended to use `tokenId` rather than `id`.
* File Format

  ```json
  [
  	{
  		"id": number,  // token ID
  		"tokenId": string,  // string type of token ID
  		"filename": string,  // file name of psd/psb file
  		"traits": List<string>  // array of full paths of image layers
  	},
  	...
  ]
  ```
* Example JSON file
  * Case 1: Previous Trait Mapper with only `id`

    ```
    [
    	{
    		"tokenId": "0",
    		"filename": "CollectionName_A_v01.psb",
    		"traits": [
    			"Body/BlueAndYellowJacket",
    			"Head/Tan",
    			"Face/Eyes/BlackLeftEye",
    			 ...
    			"Hair/PurpleLong"
    		]
    	},
    	{
    		"tokenId": "2",
    		"filename": "CollectionName_A_v01.psb",
    		"traits": [
    			"Body/PurpleSweaterWithSatchel",
    			"Head/Gradient2",
    			"Face/Eyes/BlackLeftEye",
    			 ...
    			"Hair/WhiteBucketCap"
    		]
    	},
    	...
    	{
    		"tokenId": "123456",
    		"filename": "CollectionName_B_v01.psb",
    		"traits": [
    			"Body/PinkFleece",
    			"Head/Yellow",
    			"Face/Eyes/BlackLeftEye",
    			 ...
    			"Hair/BlueMessy"
    		]
    	}
    ]
    ```
  * Case 2: New Field wth only `tokenId`
  * Case 3: Mix of `id` and `tokenId`

    ```json
    [
    	{
    		"id": 0,
    		"tokenId": "0",
    		"filename": "CollectionName_A_v01.psb",
    		"traits": [
    			"Body/BlueAndYellowJacket",
    			"Head/Tan",
    			"Face/Eyes/BlackLeftEye",
    			 ...
    			"Hair/PurpleLong"
    		]
    	},
    	{
    		"id": 2,
    		"filename": "CollectionName_A_v01.psb",
    		"traits": [
    			"Body/PurpleSweaterWithSatchel",
    			"Head/Gradient2",
    			"Face/Eyes/BlackLeftEye",
    			 ...
    			"Hair/WhiteBucketCap"
    		]
    	},
    	...
    	{
    		"tokenId": "123456",
    		"filename": "CollectionName_B_v01.psb",
    		"traits": [
    			"Body/PinkFleece",
    			"Head/Yellow",
    			"Face/Eyes/BlackLeftEye",
    			 ...
    			"Hair/BlueMessy"
    		]
    	}
    ]
    ```