What Is Mint Close Authority?
The Token Extension Program's MintCloseAuthority mint extension lets a
designated authority close a mint account and reclaim its rent once the mint's
total supply reaches zero.
Without this extension, a mint account cannot be closed.
- The total supply must be zero, so all tokens in all token accounts must be burned before a mint can be closed
- Only the configured close authority can close the mint
How to Create and Close a Mint
To create and close a mint:
- Calculate the mint account size and rent needed for the mint and the
MintCloseAuthorityextension. - Create the mint account with
CreateAccount, initializeMintCloseAuthority, and initialize the mint withInitializeMint. - If the total supply is zero, the mint account can be closed with
CloseAccount, signed by the close authority.
Calculate account size
Calculate the mint account size for the base mint plus the
MintCloseAuthority extension. This is the size used in
CreateAccount.
const client = await createClient().use(generatedPayer()).use(solanaRpc({rpcUrl: "http://localhost:8899",rpcSubscriptionsUrl: "ws://localhost:8900"})).use(rpcAirdrop()).use(airdropPayer(lamports(1_000_000_000n)));const mint = await generateKeyPairSigner();const destination = await generateKeyPairSigner();const mintCloseAuthorityExtension = extension("MintCloseAuthority", {closeAuthority: client.payer.address});const mintSpace = BigInt(getMintSize([mintCloseAuthorityExtension]));
Calculate rent
Calculate rent using the size needed for the mint plus the
MintCloseAuthority extension.
const client = await createClient().use(generatedPayer()).use(solanaRpc({rpcUrl: "http://localhost:8899",rpcSubscriptionsUrl: "ws://localhost:8900"})).use(rpcAirdrop()).use(airdropPayer(lamports(1_000_000_000n)));const mint = await generateKeyPairSigner();const destination = await generateKeyPairSigner();const mintCloseAuthorityExtension = extension("MintCloseAuthority", {closeAuthority: client.payer.address});const mintSpace = BigInt(getMintSize([mintCloseAuthorityExtension]));const mintRent = await client.rpc.getMinimumBalanceForRentExemption(mintSpace).send();
Create the mint account
Create the mint account with the calculated space and lamports.
const client = await createClient().use(generatedPayer()).use(solanaRpc({rpcUrl: "http://localhost:8899",rpcSubscriptionsUrl: "ws://localhost:8900"})).use(rpcAirdrop()).use(airdropPayer(lamports(1_000_000_000n)));const mint = await generateKeyPairSigner();const destination = await generateKeyPairSigner();const mintCloseAuthorityExtension = extension("MintCloseAuthority", {closeAuthority: client.payer.address});const mintSpace = BigInt(getMintSize([mintCloseAuthorityExtension]));const mintRent = await client.rpc.getMinimumBalanceForRentExemption(mintSpace).send();await client.sendTransaction([getCreateAccountInstruction({payer: client.payer,newAccount: mint,lamports: mintRent,space: mintSpace,programAddress: TOKEN_2022_PROGRAM_ADDRESS})]);
Initialize MintCloseAuthority
Initialize the MintCloseAuthority extension on the mint.
const client = await createClient().use(generatedPayer()).use(solanaRpc({rpcUrl: "http://localhost:8899",rpcSubscriptionsUrl: "ws://localhost:8900"})).use(rpcAirdrop()).use(airdropPayer(lamports(1_000_000_000n)));const mint = await generateKeyPairSigner();const destination = await generateKeyPairSigner();const mintCloseAuthorityExtension = extension("MintCloseAuthority", {closeAuthority: client.payer.address});const mintSpace = BigInt(getMintSize([mintCloseAuthorityExtension]));const mintRent = await client.rpc.getMinimumBalanceForRentExemption(mintSpace).send();await client.sendTransaction([getCreateAccountInstruction({payer: client.payer,newAccount: mint,lamports: mintRent,space: mintSpace,programAddress: TOKEN_2022_PROGRAM_ADDRESS}),getInitializeMintCloseAuthorityInstruction({mint: mint.address,closeAuthority: client.payer.address})]);
Initialize the mint
Initialize the mint with InitializeMint in the same transaction.
const client = await createClient().use(generatedPayer()).use(solanaRpc({rpcUrl: "http://localhost:8899",rpcSubscriptionsUrl: "ws://localhost:8900"})).use(rpcAirdrop()).use(airdropPayer(lamports(1_000_000_000n)));const mint = await generateKeyPairSigner();const destination = await generateKeyPairSigner();const mintCloseAuthorityExtension = extension("MintCloseAuthority", {closeAuthority: client.payer.address});const mintSpace = BigInt(getMintSize([mintCloseAuthorityExtension]));const mintRent = await client.rpc.getMinimumBalanceForRentExemption(mintSpace).send();await client.sendTransaction([getCreateAccountInstruction({payer: client.payer,newAccount: mint,lamports: mintRent,space: mintSpace,programAddress: TOKEN_2022_PROGRAM_ADDRESS}),getInitializeMintCloseAuthorityInstruction({mint: mint.address,closeAuthority: client.payer.address}),getInitializeMintInstruction({mint: mint.address,decimals: 0,mintAuthority: client.payer.address,freezeAuthority: client.payer.address})]);
Instruction Order
InitializeMintCloseAuthority must come before InitializeMint.
CreateAccount, InitializeMintCloseAuthority, and
InitializeMint must be included in the same transaction.
Source Reference
| Item | Description | Source |
|---|---|---|
MintCloseAuthority | Mint extension that stores the authority allowed to close a mint once its supply reaches zero. | Source |
InitializeMintCloseAuthority | Instruction that initializes the mint close authority before InitializeMint. | Source |
CloseAccount | Base token instruction that closes the mint account after the total supply reaches zero. | Source |
process_initialize_mint_close_authority | Processor logic that writes the MintCloseAuthority extension onto an uninitialized mint. | Source |
process_close_account | Shared close-account handler that enforces the zero-supply rule for mints with close authority. | Source |
Typescript
The Kit example below uses the generated instructions directly. Legacy
examples using @solana/web3.js and @solana/spl-token are included for
reference.
Kit
import { lamports, createClient, generateKeyPairSigner } from "@solana/kit";import { solanaRpc, rpcAirdrop } from "@solana/kit-plugin-rpc";import { generatedPayer, airdropPayer } from "@solana/kit-plugin-signer";import { getCreateAccountInstruction } from "@solana-program/system";import {extension,findAssociatedTokenPda,getBurnCheckedInstruction,getCloseAccountInstruction,getCreateAssociatedTokenInstructionAsync,getInitializeMintCloseAuthorityInstruction,getInitializeMintInstruction,getMintSize,getMintToCheckedInstruction,TOKEN_2022_PROGRAM_ADDRESS} from "@solana-program/token-2022";const client = await createClient().use(generatedPayer()).use(solanaRpc({rpcUrl: "http://localhost:8899",rpcSubscriptionsUrl: "ws://localhost:8900"})).use(rpcAirdrop()).use(airdropPayer(lamports(1_000_000_000n)));const mint = await generateKeyPairSigner();const destination = await generateKeyPairSigner();const mintCloseAuthorityExtension = extension("MintCloseAuthority", {closeAuthority: client.payer.address});const mintSpace = BigInt(getMintSize([mintCloseAuthorityExtension]));const mintRent = await client.rpc.getMinimumBalanceForRentExemption(mintSpace).send();await client.sendTransaction([getCreateAccountInstruction({payer: client.payer,newAccount: mint,lamports: mintRent,space: mintSpace,programAddress: TOKEN_2022_PROGRAM_ADDRESS}),getInitializeMintCloseAuthorityInstruction({mint: mint.address, // Mint account that stores the MintCloseAuthority extension.closeAuthority: client.payer.address // Authority allowed to close the mint.}),getInitializeMintInstruction({mint: mint.address,decimals: 0,mintAuthority: client.payer.address,freezeAuthority: client.payer.address})]);const [token] = await findAssociatedTokenPda({mint: mint.address,owner: client.payer.address,tokenProgram: TOKEN_2022_PROGRAM_ADDRESS});await client.sendTransaction([await getCreateAssociatedTokenInstructionAsync({payer: client.payer,mint: mint.address,owner: client.payer.address}),getMintToCheckedInstruction({mint: mint.address,token,mintAuthority: client.payer,amount: 1n,decimals: 0})]);await client.sendTransaction([getBurnCheckedInstruction({mint: mint.address,account: token,authority: client.payer,amount: 1n,decimals: 0}),getCloseAccountInstruction({account: mint.address, // Mint account to close.destination: destination.address, // Account receiving the reclaimed lamports.owner: client.payer // Close authority signing the instruction.})]);const mintInfo = await client.rpc.getAccountInfo(mint.address).send();console.log("Mint Address:", mint.address);console.log("Destination Address:", destination.address);console.log("Mint Closed:", mintInfo.value === null);
Web3.js
import {Connection,Keypair,sendAndConfirmTransaction,SystemProgram,Transaction,LAMPORTS_PER_SOL} from "@solana/web3.js";import {createInitializeMintInstruction,ExtensionType,getMintLen,createInitializeMintCloseAuthorityInstruction,TOKEN_2022_PROGRAM_ID,createCloseAccountInstruction} from "@solana/spl-token";const connection = new Connection("http://localhost:8899", "confirmed");const latestBlockhash = await connection.getLatestBlockhash();const feePayer = Keypair.generate();const destination = Keypair.generate();const airdropSignature = await connection.requestAirdrop(feePayer.publicKey,5 * LAMPORTS_PER_SOL);await connection.confirmTransaction({blockhash: latestBlockhash.blockhash,lastValidBlockHeight: latestBlockhash.lastValidBlockHeight,signature: airdropSignature});const mint = Keypair.generate();const extensions = [ExtensionType.MintCloseAuthority];const mintLength = getMintLen(extensions);const mintRent = await connection.getMinimumBalanceForRentExemption(mintLength);const createAccountInstruction = SystemProgram.createAccount({fromPubkey: feePayer.publicKey,newAccountPubkey: mint.publicKey,space: mintLength,lamports: mintRent,programId: TOKEN_2022_PROGRAM_ID});const initializeMintCloseAuthorityInstruction =createInitializeMintCloseAuthorityInstruction(mint.publicKey, // Mint account that stores the MintCloseAuthority extension.feePayer.publicKey, // Authority allowed to close the mint.TOKEN_2022_PROGRAM_ID // Token program that owns the mint.);const initializeMintInstruction = createInitializeMintInstruction(mint.publicKey, // mint pubkey9, // decimalsfeePayer.publicKey, // mint authorityfeePayer.publicKey, // freeze authorityTOKEN_2022_PROGRAM_ID);const transaction = new Transaction({feePayer: feePayer.publicKey,blockhash: latestBlockhash.blockhash,lastValidBlockHeight: latestBlockhash.lastValidBlockHeight}).add(createAccountInstruction,initializeMintCloseAuthorityInstruction,initializeMintInstruction);const transactionSignature = await sendAndConfirmTransaction(connection,transaction,[feePayer, mint]);console.log("Mint Address:", mint.publicKey.toBase58());console.log("Transaction Signature:", transactionSignature);const latestBlockhash2 = await connection.getLatestBlockhash();const closeMintInstruction = createCloseAccountInstruction(mint.publicKey, // Mint account to close.destination.publicKey, // Account receiving the reclaimed lamports.feePayer.publicKey, // Close authority signing the instruction.[], // Additional multisig signers.TOKEN_2022_PROGRAM_ID // Token program that owns the mint.);const closeMintTransaction = new Transaction({feePayer: feePayer.publicKey,blockhash: latestBlockhash2.blockhash,lastValidBlockHeight: latestBlockhash2.lastValidBlockHeight}).add(closeMintInstruction);const transactionSignature3 = await sendAndConfirmTransaction(connection,closeMintTransaction,[feePayer]);console.log("\nDestination Address:", destination.publicKey.toBase58());console.log("Transaction Signature:", transactionSignature3);
Rust
use anyhow::Result;use solana_client::nonblocking::rpc_client::RpcClient;use solana_commitment_config::CommitmentConfig;use solana_sdk::{signature::{Keypair, Signer},transaction::Transaction,};use solana_system_interface::instruction::create_account;use spl_token_2022_interface::{extension::{mint_close_authority::MintCloseAuthority, BaseStateWithExtensions, ExtensionType,StateWithExtensions,},instruction::{close_account, initialize_mint, initialize_mint_close_authority},state::Mint,ID as TOKEN_2022_PROGRAM_ID,};#[tokio::main]async fn main() -> Result<()> {let client = RpcClient::new_with_commitment(String::from("http://localhost:8899"),CommitmentConfig::confirmed(),);let fee_payer = Keypair::new();let destination = Keypair::new();let airdrop_signature = client.request_airdrop(&fee_payer.pubkey(), 5_000_000_000).await?;loop {let confirmed = client.confirm_transaction(&airdrop_signature).await?;if confirmed {break;}}let mint = Keypair::new();let mint_space =ExtensionType::try_calculate_account_len::<Mint>(&[ExtensionType::MintCloseAuthority])?;let mint_rent = client.get_minimum_balance_for_rent_exemption(mint_space).await?;let create_account_instruction = create_account(&fee_payer.pubkey(), // payer&mint.pubkey(), // new account (mint)mint_rent, // lamportsmint_space as u64, // space&TOKEN_2022_PROGRAM_ID, // program id);let initialize_close_mint_instruction = initialize_mint_close_authority(&TOKEN_2022_PROGRAM_ID, // token program&mint.pubkey(), // mintSome(&fee_payer.pubkey()), // close authority)?;let initialize_mint_instruction = initialize_mint(&TOKEN_2022_PROGRAM_ID, // token program&mint.pubkey(), // mint&fee_payer.pubkey(), // mint authoritySome(&fee_payer.pubkey()), // freeze authority9, // decimals)?;let transaction = Transaction::new_signed_with_payer(&[create_account_instruction,initialize_close_mint_instruction,initialize_mint_instruction,],Some(&fee_payer.pubkey()),&[&fee_payer, &mint],client.get_latest_blockhash().await?,);client.send_and_confirm_transaction(&transaction).await?;println!("Mint Address: {}", mint.pubkey());let mint_account = client.get_account(&mint.pubkey()).await?;let mint_state = StateWithExtensions::<Mint>::unpack(&mint_account.data)?;let mint_extension_types = mint_state.get_extension_types()?;println!("\nMint extensions enabled: {:?}", mint_extension_types);let mint_close_authority = mint_state.get_extension::<MintCloseAuthority>()?;println!("\n{:#?}", mint_close_authority);let close_mint_instruction = close_account(&TOKEN_2022_PROGRAM_ID, // Token program that owns the mint.&mint.pubkey(), // Mint account to close.&destination.pubkey(), // Account receiving the reclaimed lamports.&fee_payer.pubkey(), // Close authority signing the instruction.&[&fee_payer.pubkey()], // Additional multisig signers.)?;let transaction = Transaction::new_signed_with_payer(&[close_mint_instruction],Some(&fee_payer.pubkey()),&[&fee_payer],client.get_latest_blockhash().await?,);client.send_and_confirm_transaction(&transaction).await?;match client.get_account(&mint.pubkey()).await {Ok(_) => println!("\nMint account still exists (unexpected)"),Err(e) => println!("\nMint account successfully closed: {:#?}", e),}Ok(())}
Is this page helpful?