Crossmint’s minting infrastructure can validate and upload metadata to decentralized storage on your behalf. Crossmint will default to IPFS. If you are interested in using Arweave, contact us. If you want to upload and manage the metadata yourself, simply pass the url to the API and flag reuploadLinkedFiles as false.

Collection and NFT metadata (e.g. title, description, image) must be specified in JSON format and follow industry conventions to ensure it renders appropriately across wallets and marketplaces.

Crossmint supports rich metadata like audio, video, and HTML. To include rich metadata, simply populate animation_url as specified in the links below.

File size limits

Crossmint’s standard plan has a 10mb file size limit. For larger uploads, you must upgrade to a premium plan or handle the upload yourself.

Metadata standards differ slightly across blockchains:

EVM chains follow the OpenSea standard. Refer to their official documentation to see what attributes can be included and how. Note that name and image are mandatory fields.

EVM Metadata Example
{
  "name": "Crossmint Test NFT",
  "description": "Created with the Crossmint minting API",
  "image": "https://bafkreiexjl6kw4khdxkrt6dojgacscnzvrys47t472l2t7d6r2ss65kifq.ipfs.nftstorage.link/",
  "external_url": "https://docs.crossmint.com",
  "attributes":  [
    {
      "trait_type": "background",
      "value": "black"
    },
    {
      "trait_type": "flavor",
      "value": "minty"
    }
  ]
}

​
FAQs

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