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Issue an NFT (SDK)

The SDK equivalent of Issuing and managing an NFT. On-chain, an NFT is an MLS-03 issuance carrying the creator, name, description, ticker, icon, media URI, and media hash; the JSON standard for the off-chain metadata is defined in the Token Metadata Standards.

Immutable by design

NFT metadata is set at issuance and cannot be changed: there is no equivalent of changeMetadataUri for NFTs. Compute and record the media hash before issuing: Mintlayer does not prescribe an algorithm, use a standard one (e.g. SHA-256) and record which one you used.

Issuing​

JavaScript

const signedTx = await client.issueNft({
  ticker: 'SUNST',
  name: 'Sunset #1',
  description: 'A photograph of a sunset',
  creator: 'tmt1q...', // optional
  media_uri: 'https://example.com/sunset.png',
  media_hash: '<sha-256 hex hash of the media>',
  icon_uri: 'https://example.com/icon.png',
  additional_metadata_uri: 'https://example.com/sunset.json', // optional extended metadata
  destination: 'tmt1q...', // where the NFT is minted
});

Go

import "github.com/mintlayer/go-sdk/wallet"

wc := wallet.New("http://127.0.0.1:3034")

ownerAddr, err := wc.NewAddress(ctx, 0)

result, err := wc.IssueNFT(ctx, wallet.IssueNFTParams{
    Account:            0,
    DestinationAddress: ownerAddr,
    Metadata: wallet.NFTMetadata{
        Name:        "Sunset #1",
        Description: "A photograph of a sunset",
        Ticker:      "SUNST",
        MediaHash:   "a3f1e2...d9c4",
        MediaURI:    stringPtr("https://example.com/sunset.png"),
        IconURI:     stringPtr("https://example.com/icon.png"),
    },
})
fmt.Printf("nft id: %s\n", result.TokenID)

Each issuance transaction creates exactly one NFT, there is no mint step afterwards.

Transferring​

JavaScript

await client.transferNft({ to: 'tmt1q...', token_id: 'tmltk1...' });

Go: an NFT transfer is a token transfer of the NFT id; use the wallet transaction APIs (see Go SDK: Wallet) or the wasm output encoders.

Reading NFT state​

Go (indexer):

import "github.com/mintlayer/go-sdk/indexer"

idx := indexer.New("http://127.0.0.1:3000")

nft, err := idx.GetNFT(ctx, result.TokenID)
fmt.Printf("owner: %s  name: %s\n", nft.Owner, nft.Metadata.Name)

JavaScript: NFTs held by the connected addresses appear in client.getTokensOwned() / getBalances().

Metadata standard​

For the JSON document at the metadata URI (media details, editions, licensing, collections), follow the MLS-03 schema in Token Metadata Standards, it includes ready-made templates for art, gaming, tickets, credentials, and more.