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Issue an NFT

The JavaScript path to issuing MLS-03 NFTs with @mintlayer/sdk. The same workflow in Go lives in the Go guides; the wallet-cli version is 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​

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
});

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

Transferring​

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

Reading NFT state​

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