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Issue an NFT

The Rust path to issuing MLS-03 NFTs. The same workflow exists for the command line, Go, and JavaScript. 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 change_token_metadata_uri 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 via the wallet daemon​

Each NFT issuance transaction creates exactly one NFT on an existing token; there is no post-issuance minting.

use mintlayer_sdk::wallet::{IssueNftParams, NftMetadata, TxOptions};

let result = c.issue_nft(IssueNftParams {
    account: 0,
    destination_address: authority.clone(),
    metadata: NftMetadata {
        media_hash: "hex-encoded sha256 of the media".into(),
        name: "My NFT".into(),
        description: "A unique digital collectible".into(),
        ticker: "MYNFT".into(),
        creator: None,      // Option<String>, public key hex
        icon_uri: None,
        media_uri: Some("https://example.com/media.png".into()),
        additional_metadata_uri: None,
    },
    options: TxOptions::default(),
}).await?;
println!("nft id: {}", result.token_id);

Full-custody issuance​

With the crypto feature, build the issuance output yourself; the issuance fee (crypto::nft_issuance_fee(height, network)) must be covered by the transaction's coin inputs:

let nft_output = crypto::encode_output_issue_nft(
    &token_id,               // existing collection token id
    "mtc1q_authority...", "My NFT", "MYNFT", "A unique digital collectible",
    media_hash_bytes,        // &[u8]
    None,                    // Option<PublicKey> creator
    Some("https://example.com/media.png"),
    None, None,              // icon_uri, additional_metadata_uri
    network,
)?;

Reading NFT state​

The indexer reports NFTs with owner and metadata:

let nft = idx.nft(&result.token_id).await?;
println!("owner: {}", nft.owner);

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.