What is ERC721 on Solana?

If you're coming from the EVM ecosystem, one thing you know well is ERC721. NFTs (non-fungible tokens) are at the heart of many blockchain applications, and ERC721 is one of the first standards developers learn when deploying NFT collections. On Solana, what is the ERC721 equivalent and how does it differ?

ERC721 sets a standard for Non-Fungible Tokens (NFTs), meaning each token is unique (in type and value) compared to another token. The ERC721 standard is utilized to represent individual tokens with distinct identifiers. Unlike ERC20 tokens, ERC721 tokens can possess unique characteristics and functions.

Token Program（プラスメタデータ）

Solanaでは、NFTコレクションごとに新しいスマートコントラクトは存在しません。代わりに、NFTは単一のオンチェーンToken Programの下で作成されます。これは代替可能トークンに使用されるものと同じプログラムで、供給量を1にしてミントされるだけです。NFTの追加詳細（名前、シンボル、画像URIなど）を保存するために、開発者はMetaplex Token Metadata Programを使用します。

Metaplex Metadataは、NFT（非代替性トークン）とデジタルアセットのためのオープンソースプロトコル兼プラットフォームです。Solanaブロックチェーン上に構築され、MetaplexはSolana上のトークンに追加のメタデータを付与することを容易にします。

これは、通常コレクションごとに新しいERC721コントラクトをデプロイするEthereumとは異なります。なぜSolana上のNFTには単一の主要プログラムがあるのでしょうか？それは、状態（データ）と実行ロジック（プログラム）を分離するSolanaアカウントモデルによるものです。Solanaはすべてのトークンに対してToken Programを再利用するため、新しいNFTコントラクトを作成してデプロイする必要はなく、供給量=1の新しいmint accountを作成するだけです。

NFTs Don't Have Contract Addresses, Only Mint Addresses

On Ethereum, each NFT collection is identified by its Contract Address, and each token has a unique tokenId within that contract. On Solana, each NFT is identified by a Mint Address. The difference is that you don't deploy a separate "NFT contract" - you just instruct the universal Token Program to create a new mint.

Because Solana's Token Program is universal, there's no concept of a unique "NFT contract address." Instead, each NFT is a special SPL token (supply of 1) with its own Mint Address.

If you want a "collection," you group multiple mint addresses together via a Collection Address in Metaplex, but each minted NFT is still just an SPL token with a unique Mint Address.

No Approval Flow Needed

On Ethereum, ERC721 often relies on approve or setApprovalForAll for external marketplaces or dApps to transfer your NFTs. On Solana, each NFT is stored in a user's ATA(Associated token account), and a single transaction can include any necessary steps. There's no separate approval flow - one atomic transaction can handle all instructions (e.g. transfer ownership, update metadata, etc.).

What Does A Solana Token Program Look Like?

A very rough translation of the Solana Token Program would look like this:

solidity

// SPDX-License-Identifier: MIT license
pragma solidity =0.8.28;

struct Mint {
    uint8 decimals;
    uint256 supply;
    address mintAuthority;
    address freezeAuthority;
    address mintAddress;
}

struct TokenAccount {
    address mintAddress;
    address owner;
    uint256 balance;
    bool isFrozen;
}

struct Metadata {
    string name;
    string symbol;
    string tokenURI;
}

contract Spl721 {
    mapping(address => Mint) public mints;
    mapping(address => TokenAccount) public tokenAccounts;
    mapping(address => Metadata) public nftMetadata;
    mapping(address => bool) public mintAddresses;
    mapping(address => bool) public tokenAddresses;

    function initializeMint(
        uint8 decimals,
        address mintAuthority,
        address freezeAuthority,
        address mintAddress
    )
        public
        returns (Mint memory)
    {
        require(!mintAddresses[mintAddress], "Mint already exists");
        mints[mintAddress] = Mint(decimals, 0, mintAuthority, freezeAuthority, mintAddress);
        mintAddresses[mintAddress] = true;
        return mints[mintAddress];
    }

    function setMetadata(
        address mintAddress,
        string memory name,
        string memory symbol,
        string memory tokenURI
    )
        public
    {
        require(mintAddresses[mintAddress], "Mint does not exist");
        nftMetadata[mintAddress] = Metadata(name, symbol, tokenURI);
    }

    function mintNFT(address toMintTokens, address mintAddress) public {
        require(mintAddresses[mintAddress], "NFT mint does not exist");
        require(mints[mintAddress].mintAuthority == msg.sender, "Only the mint authority can mint");
        require(mints[mintAddress].supply == 0, "NFT already minted");
        mints[mintAddress].supply = 1;
        address tokenAddress = address(uint160(uint256(keccak256(abi.encodePacked(toMintTokens, mintAddress)))));
        if (!tokenAddresses[tokenAddress]) {
            tokenAccounts[tokenAddress] = TokenAccount(mintAddress, toMintTokens, 0, false);
            tokenAddresses[tokenAddress] = true;
        }
        tokenAccounts[tokenAddress].balance = 1;
        tokenAccounts[tokenAddress].owner = toMintTokens;
    }

    function transfer(address to, address mintAddress, uint256 amount) public {
        address toTokenAddress = address(uint160(uint256(keccak256(abi.encodePacked(to, mintAddress)))));
        address fromTokenAddress = address(uint160(uint256(keccak256(abi.encodePacked(msg.sender, mintAddress)))));
        require(tokenAccounts[fromTokenAddress].balance >= amount, "Insufficient balance");
        require(amount == 1, "Only transferring 1 NFT at a time");
        require(tokenAccounts[fromTokenAddress].owner == msg.sender, "Not the NFT owner");
        require(!tokenAccounts[fromTokenAddress].isFrozen, "Sender token account is frozen");
        if (tokenAddresses[toTokenAddress]) {
            require(!tokenAccounts[toTokenAddress].isFrozen, "Receiver token account is frozen");
        }
        if (!tokenAddresses[toTokenAddress]) {
            tokenAccounts[toTokenAddress] = TokenAccount(mintAddress, to, 0, false);
            tokenAddresses[toTokenAddress] = true;
        }
        tokenAccounts[fromTokenAddress].balance -= amount;
        tokenAccounts[toTokenAddress].balance += amount;
        tokenAccounts[toTokenAddress].owner = to;
    }

    function freezeAccount(address owner, address mintAddress) public {
        require(mintAddresses[mintAddress], "Mint does not exist");
        require(mints[mintAddress].freezeAuthority == msg.sender, "Only the freeze authority can freeze");
        address tokenAddress = address(uint160(uint256(keccak256(abi.encodePacked(owner, mintAddress)))));
        require(tokenAddresses[tokenAddress], "Token account not found");
        tokenAccounts[tokenAddress].isFrozen = true;
    }

    function getMint(address token) public view returns (Mint memory) {
        return mints[token];
    }

    function getTokenAccount(address owner, address token) public view returns (TokenAccount memory) {
        return tokenAccounts[address(uint160(uint256(keccak256(abi.encodePacked(owner, token)))))];
    }

    function getMetadata(address mintAddress) public view returns (Metadata memory) {
        return nftMetadata[mintAddress];
    }
}

As you can see in the contract, instead of an approval flow, there is only a transfer function to move tokens. On Solana, a single transaction can call multiple smart contract functions atomically, removing the need for the approval flow. Another difference is that everything is stored in a token account on Solana, keeping the details of the owner's tokens separate from the other state.

Where's the NFT Metadata?

On Ethereum, ERC721 contracts often store a metadata URI or embed logic for fetching token metadata. On Solana, the Token Metadata Program (by Metaplex) handles NFT metadata in a separate account. You can include fields like name, symbol, description, image URI, and more--all without changing the underlying Token Program. This does mean there's a separate instruction in your minting transaction to attach metadata. Since Solana can handle multiple program calls atomically in one transaction, you can easily create the mint and set up metadata in a single go.

Tradeoffs of Each Approach

Now that you have a general idea of how the token program and metadata program on Solana works, let's go through some of the tradeoffs of each NFT standard.

ERC721

Highly customizable contracts
New contract deployment for each collection
Hard to index across many contracts
Metadata often defined in contract or via URIs
Requires individual audits

Solana NFT (SPL + Metaplex)

Single program for all NFTs
New NFTs created by transactions, not by new contracts
Easier to index since there's one main program
Metadata stored in a separate program
Reuses existing audited code

High-Level Comparison

Below is a table comparing the basic steps of deploying an ERC-721 token on Ethereum vs. creating an NFT (SPL token with metadata) on Solana. (On Solana, you can freely mint SPL tokens by using the spl-token command in the command-line tool.)

ステップ	Ethereum (ERC-721)	Solana (SPL + Metaplex)
1. トークンコードの準備	通常、OpenZeppelinのERC721ライブラリを使用します。Solidityファイル(例:MyNFT.sol)を作成します。	基本的なNFT機能にカスタムコントラクトは不要です。Token Programは既にデプロイされています。Mint Account(供給量=1)を作成するだけです。
2. コンパイル&デプロイ	Hardhat/Truffleを使用してコンパイルおよびデプロイします(例:`npx hardhat run deploy.js --network ...`)。	CLI(例:`spl-token create-token --decimals 0`)またはSDKツール(MetaplexのCandy Machineなど)を使用します。個別のコントラクトデプロイは不要です。
3. NFTのミント	コントラクトの`mint()`関数を呼び出し、NFTをアドレスに割り当て、通常はトークンメタデータURIを設定します。ガス代は変動します。	`spl-token mint <MINT_ADDRESS> 1`を実行するか、Metaplexのミントinstructionsを使用して正確に1の供給量を作成します。Solanaのトランザクション手数料は通常非常に低額です。
4. 受取人の作成	通常は一般的なEthereumアドレスです。多くのウォレットでNFTを表示するには、ユーザーがNFTコントラクトアドレスを追加する必要があります。	各ユーザーはassociated token accountを持っています。Phantomなどのウォレットは、NFT用のATAを自動的に認識します。トークンを「追加」する追加手順は不要ですが、認識されると「コレクティブル」タブに表示される場合があります。
5. 結果の確認	EtherscanまたはOpenSeaなどのNFTマーケットプレイスで確認します。多くの場合、一部のウォレットでトークンを表示するには、ユーザーが手動でコントラクトアドレスを追加する必要があります。	`solana balance <ADDRESS>`または`spl-token accounts`を使用してトークン保有量を確認します。Solana ExplorerまたはNFTマーケットプレイス(Magic Eden、OpenSea Solanaなど)を使用してNFTの存在を確認することもできます。
6. 一意の識別子	コントラクトアドレス + `tokenId`。	Mint Address。各NFTは単に`供給量=1`のSPLトークンです。
7. コレクション	1つのコントラクト内のすべてのトークンは、通常1つのコレクションを表します。	コレクションはMetaplexの「コレクションアドレス」を介して割り当てられます。専用のコントラクトをデプロイする必要はありません。
8. コードの更新	大規模なアップグレードの場合、プロキシパターンを使用するか、コントラクトを再デプロイする可能性があります。通常、これは上級開発者のみが行います。	Token Programは固定されています。高度な機能(ロイヤリティ、動的メタデータなど)が必要な場合は、個別のオンチェーンプログラムを使用または構築できます。MetaplexはプログラマブルNFTなどの拡張機能もサポートしています。
9. 監査要件	各コントラクトは通常、特にカスタムミントロジックやマーケットプレイスなどを追加する場合、監査が必要です。	主要なToken ProgramとMetaplex Metadata Programは複数回監査されています。標準的なNFTのミントには、通常、追加のコントラクト監査は不要です。

Want to mint your own NFT on Solana? Check out this guide!

How to do ERC721 on Solana

Let's explore how to interact with the Token Program using solana/web3.js based on Ethereum's ERC721 interface structure.

As mentioned above, since NFT Collections on Solana are not tied to a specific contract, the concept of a tokenId does not exist. Therefore, to find the specific data of a token, you should use Mint Address or Collection Address.

How to do `name()`

solidity

function name() external view returns (string); // Returns the token collection name

You can use @metaplex-foundation/umi-bundle-defaults and @metaplex-foundation/mpl-token-metadata to fetch and parse an NFT's off-chain metadata from its mint address.

jsx

import { createUmi } from "@metaplex-foundation/umi-bundle-defaults";
import { fetchDigitalAsset, mplTokenMetadata } from "@metaplex-foundation/mpl-token-metadata";
import { PublicKey } from "@metaplex-foundation/js";
const mintAddress = new PublicKey("Token Address");

async function name() {
  try {
    const umi = createUmi("https://api.devnet.solana.com");
    umi.use(mplTokenMetadata());
    const digitalAsset = await fetchDigitalAsset(umi, mintAddress);
    return digitalAsset.metadata.name;
  } catch (error) {
    console.error("Error fetching NFT name:", error);
    return null;
  }
}

name().then(nftName => {
    console.log("NFT Name:", nftName);
  })
  .catch(error => {
    console.error("Error:", error);
  });

How to do `symbol()`

solidity

function symbol() external view returns (string); // Returns the token collection symbol

You can also retrieve the symbol in the same way as name(), using @metaplex-foundation/umi-bundle-defaults and @metaplex-foundation/mpl-token-metadata.

jsx

import { createUmi } from "@metaplex-foundation/umi-bundle-defaults";
import { fetchDigitalAsset, mplTokenMetadata } from "@metaplex-foundation/mpl-token-metadata";
import { PublicKey } from "@metaplex-foundation/js";
const mintAddress = new PublicKey("Token Address");

async function symbol() {
  try {
    const umi = createUmi("https://api.devnet.solana.com");
    umi.use(mplTokenMetadata());
    const digitalAsset = await fetchDigitalAsset(umi, mintAddress);
    return digitalAsset.metadata.symbol;
  } catch (error) {
    console.error("Error fetching NFT symbol:", error);
    return null;
  }
}

symbol().then(nftSymbol => {
  console.log("NFT Symbol:", nftSymbol);
}).catch(error => {
  console.error("Error:", error);
});

How to do `tokenURI()`

bash

function tokenURI(uint256 _tokenId) external view returns (string); // Returns the tokenURI of the token

You can also retrieve the symbol in the same way as name(), using @metaplex-foundation/umi-bundle-defaults and @metaplex-foundation/mpl-token-metadata.

jsx

import { createUmi } from "@metaplex-foundation/umi-bundle-defaults";
import { fetchDigitalAsset, mplTokenMetadata } from "@metaplex-foundation/mpl-token-metadata";
import { PublicKey } from "@metaplex-foundation/js";
const mintAddress = new PublicKey("Token Address");

async function tokenURI( /* no tokenId */ ) {
  try {
    const umi = createUmi("https://api.devnet.solana.com");
    umi.use(mplTokenMetadata());
    const digitalAsset = await fetchDigitalAsset(umi, mintAddress);
    return digitalAsset.metadata.uri;
  } catch (error) {
    console.error("Error fetching token URI:", error);
    return null;
  }
}

tokenURI()
  .then(uri => {
    console.log("Token URI:", uri);
  })
  .catch(error => {
    console.error("Error:", error);
  });

How to do `ownerOf()`

bash

function ownerOf(uint256 _tokenId) public view returns (address) // Returns the owner of the tokenId token

We can check the owner of an NFT using the mint address instead of the tokenId.

jsx

import { Connection, PublicKey } from "@solana/web3.js";

const connection = new Connection("https://api.devnet.solana.com", "confirmed");
const mintAddress = new PublicKey("Token Address");

async function ownerOf( /*no tokenId*/ ){
  const largestAccounts = await connection.getTokenLargestAccounts(new PublicKey(mintAddress));
  const largestAccountInfo = await connection.getParsedAccountInfo(largestAccounts.value[0].address);
  return largestAccountInfo.value.data.parsed.info.owner;
}

ownerOf().then(owner => {
  console.log(owner);
}).catch(error => {
  console.error("Error:", error);
});

How to do `transferFrom()`

solidity

function transferFrom(address _from, address _to, uint256 _tokenId) external payable; // Transfers tokenId token from _from to _to

First, Let's look at this code for understanding logic:

On Solana, each token is identified by its unique Mint address, and users store their balances in an Associated Token Account (ATA). In a transaction, the ATA address is used as the sender or receiver for transferring tokens. Unlike on Ethereum, where you directly call an ERC-20 contract, Solana handles token transfer logic through its native system program.

We can make a transaction's transfer instruction through createTransferCheckedInstruction and send it through sendTransaction from @solana/spl-token.

jsx

import { Keypair, Transaction, Connection, PublicKey } from "@solana/web3.js";
import { createTransferCheckedInstruction } from "@solana/spl-token";

const connection = new Connection("https://api.devnet.solana.com", "confirmed");

// Replace with your real private key (as a Uint8Array)
const ownerSecretkey = [];
const ownerPrivatekeypair = Keypair.fromSecretKey(new Uint8Array(ownerSecretkey));

const fromPublicKey = ownerPrivatekeypair.publicKey; // The sender's public key
const toPublicKey = new PublicKey("Receiver's Wallet Address");

const mintAddress = new PublicKey("Token Address");

// Pre-existing ATA addresses (for `_from` and `_to`)
const ownerTokenAccount = new PublicKey("Associated Token Account of _from");
const receiverTokenAccount = new PublicKey("Associated Token Account of _to");

// For an NFT, decimals = 0 and amount = 1
async function transferFrom(_from, _to) {
  try {
    const tx = new Transaction().add(
      createTransferCheckedInstruction(
        ownerTokenAccount,              // _from's ATA
        mintAddress,
        receiverTokenAccount,           // _to's ATA
        ownerPrivatekeypair.publicKey,  // Authority for `_from` (the private key must match this public key)
        1,                              // amount = 1 NFT
        0                               // decimals = 0 for NFT
      )
    );
    
    // Send transaction (simple version)
    await connection.sendTransaction(tx, [ownerPrivatekeypair]);
    return true;
  } catch (error) {
    console.error("Error in transferFrom:", error);
    return false;
  }
}

transferFrom(fromPublicKey, toPublicKey)
  .then(result => {
    console.log("transferFrom result:", result);
  })
  .catch(error => {
    console.error("Error:", error);
  });

How we can check receiverTokenAddress through receiverAddress? We can use getOrCreateAssociatedTokenAccount. It will retrieve the associated token account, or create it if it doesn't exist.

jsx

import { Keypair, Transaction, Connection, PublicKey } from "@solana/web3.js";
import { createTransferCheckedInstruction, getOrCreateAssociatedTokenAccount } from "@solana/spl-token";

const connection = new Connection("https://api.devnet.solana.com", "confirmed");

// Insert your private key as a Uint8Array
const ownerSecretkey = [];
const ownerPrivatekeypair = Keypair.fromSecretKey(new Uint8Array(ownerSecretkey));

const fromAddress = ownerPrivatekeypair.publicKey;  // The sender's public key
const toAddress = new PublicKey("Receiver's Wallet Address");

const mintAddress = new PublicKey("Token Address");

// For an NFT: decimals = 0, amount = 1
async function transferFrom(_from, _to) {
  try {
    // Retrieve (or create if missing) the sender's ATA
    const ownerTokenAccount = await getOrCreateAssociatedTokenAccount(
      connection,
      ownerPrivatekeypair,    // Fee payer
      mintAddress,
      _from
    );

    // Retrieve (or create if missing) the receiver's ATA
    const receiverTokenAccount = await getOrCreateAssociatedTokenAccount(
      connection,
      ownerPrivatekeypair,    // Fee payer (use the receiver if needed)
      mintAddress,
      _to
    );

    // Create transaction with a transfer of 1 NFT (decimals=0)
    const tx = new Transaction().add(
      createTransferCheckedInstruction(
        ownerTokenAccount.address,
        mintAddress,
        receiverTokenAccount.address,
        ownerPrivatekeypair.publicKey,
        1, // Always transfer exactly 1 (NFT)
        0  // decimals = 0 for an NFT
      )
    );

    // Send the transaction
    await connection.sendTransaction(tx, [ownerPrivatekeypair]);
    return true;
  } catch (error) {
    console.error("Error in transferFrom:", error);
    return false;
  }
}

transferFrom(fromAddress, toAddress)
  .then(result => {
    console.log("Transaction result:", result);
  })
  .catch(error => {
    console.error("Error:", error);
  });

Want to explore more features? Check out this guide!

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Start building on Solana

What is ERC721 on Solana?

Token Program（プラスメタデータ）

NFTs Don't Have Contract Addresses, Only Mint Addresses

No Approval Flow Needed

What Does A Solana Token Program Look Like?

Where's the NFT Metadata?

Tradeoffs of Each Approach

High-Level Comparison

How to do ERC721 on Solana

How to do name()

How to do symbol()

How to do tokenURI()

How to do ownerOf()

How to do transferFrom()

Start building on Solana

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Intro to Solana Development

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More Solana Developer Tools

How to do `name()`

How to do `symbol()`

How to do `tokenURI()`

How to do `ownerOf()`

How to do `transferFrom()`