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Chain Methods API

Account management Snaps can choose to implement the following EVM methods to support dapp requests from custom accounts.

EOA methods​

The following methods are used by externally owned accounts (EOAs).

personal_sign​

Presents a plain text signature challenge to the user and returns the signed response. Equivalent to eth_sign on some other wallets, and prepends a safe prefix to the signed message to prevent the challenge tricking users into signing a financial transaction.

Parameters​

An array containing:

  1. Message to sign: string - Hex-encoded UTF-8 string to present to the user.
  2. Address: string - Address of the requested signing account.

Returns​

Signature: string - Hex-encoded signature.

Example​

{
  "method": "personal_sign",
  "params": [
    "0x4578616d706c652060706572736f6e616c5f7369676e60206d657373616765",
    "0x5874174dcf1ab6F7Efd8496f4f09404CD1c5bA84"
  ]
}

eth_signTransaction​

Signs a transaction that can be submitted to the network later using eth_sendRawTransaction.

Parameters​

An array containing:

  1. Transaction object to sign, which contains:
    • type: string - Transaction type.
    • nonce: string - Anti-replay parameter.
    • to: string - Recipient address, or null if this is a contract creation transaction.
    • from: string - Sender address.
    • value: string - Value to be transferred, in wei.
    • data: string - Compiled code of a contract OR hash of the invoked method signature and encoded parameters.
    • gasLimit: string - Gas provided by the sender.
    • gasPrice: string - (Optional) Gas price, in wei, provided by the sender.
    • maxPriorityFeePerGas: string - (Optional) Maximum fee, in wei, the sender is willing to pay per gas above the base fee.
    • maxFeePerGas:string - (Optional) Maximum total fee (base fee + priority fee), in wei, the sender is willing to pay per gas.
    • accessList: object[] - (Optional) List of addresses and storage keys the transaction plans to access.
    • chainId: string - Chain ID.

Returns​

A signature object containing:

  • v: string - ECDSA Recovery ID.
  • r: string - ECDSA signature r.
  • s: string - ECDSA signature s.

Example​

{
  "method": "eth_signTransaction",
  "params": [
    {
      "type": "0x2",
      "nonce": "0x1",
      "to": "0x0c54fccd2e384b4bb6f2e405bf5cbc15a017aafb",
      "from": "0x660265edc169bab511a40c0e049cc1e33774443d",
      "value": "0x0",
      "data": "0x",
      "gasLimit": "0x5208",
      "maxPriorityFeePerGas": "0x3b9aca00",
      "maxFeePerGas": "0x2540be400",
      "accessList": [],
      "chainId": "0xaa36a7"
    }
  ]
}

eth_signTypedData_v4​

Presents a data message for the user to sign in a structured and readable format, and returns the signed response. Introduced by EIP-712.

Parameters​

An array containing:

  1. Address: string - Address of the requested signing account.
  2. Typed data: object - Typed data object containing:
    • types: object - Types object containing:
      • EIP712Domain: array - Array specifying one or more of the following domain separator values:
        • name - User-readable name of the signing domain, that is, name of the dapp or the protocol.
        • version - Current major version of the signing domain.
        • chainId - Chain ID of the network.
        • verifyingContract - Address of the contract that will verify the signature.
        • salt - Disambiguating salt for the protocol.
    • primaryType: string - Primary type.
    • domain: object - Domain separator values specified in the EIP712Domain type.
    • message: object - Message to present to the user.

Returns​

Signature: string - Hex-encoded signature.

Example​

{
  "method": "eth_signTypedData_v4",
  "params": [
    "0xCD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826",
    {
      "types": {
        "EIP712Domain": [
          { "name": "name", "type": "string" },
          { "name": "version", "type": "string" },
          { "name": "chainId", "type": "uint256" },
          { "name": "verifyingContract", "type": "address" }
        ],
        "Person": [
          { "name": "name", "type": "string" },
          { "name": "wallet", "type": "address" }
        ],
        "Mail": [
          { "name": "from", "type": "Person" },
          { "name": "to", "type": "Person" },
          { "name": "contents", "type": "string" }
        ]
      },
      "primaryType": "Mail",
      "domain": {
        "name": "Ether Mail",
        "version": "1",
        "chainId": 1,
        "verifyingContract": "0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC"
      },
      "message": {
        "from": {
          "name": "Cow",
          "wallet": "0xCD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826"
        },
        "to": {
          "name": "Bob",
          "wallet": "0xbBbBBBBbbBBBbbbBbbBbbbbBBbBbbbbBbBbbBBbB"
        },
        "contents": "Hello, Bob!"
      }
    }
  ]
}

Deprecated methods​

Snaps can also implement deprecated signing methods that some dapps might use.

ERC-4337 methods​

Flask Only
This feature is experimental and only available in MetaMask Flask, the canary distribution of MetaMask.

The following methods are used by ERC-4337 accounts.

eth_prepareUserOperation​

Prepares a new user operation from transaction data.

Parameters​

An array containing:

  1. Transaction intents object, which contains:
    • to: string - Recipient address, or null if this is a contract creation transaction.
    • value: string - Value to be transferred, in wei.
    • data: string - Compiled code of a contract OR hash of the invoked method signature and encoded parameters.

Returns​

A user operation details object containing:

  • callData: string - Data to pass to the sender during the main execution call.
  • initCode: string - Account bytecode (needed if and only if the account is not yet onchain and needs to be created).
  • nonce: string - Anti-replay parameter.
  • gasLimits - (Optional) Gas limits object containing:
    • callGasLimit: string - Amount of gas to allocate to the main execution call.
    • verificationGasLimit: string - Amount of gas to allocate to the verification step.
    • preVerificationGas: string - Amount of gas to compensate the bundler for pre-verification execution, to pay for callData, and to account for overhead that can't be tracked onchain.
  • dummySignature: string - Dummy signature.
  • dummyPaymasterAndData: string - Dummy paymasterAndData.
  • bundlerUrl: string - Bundler URL.

Example​

{
  "method": "eth_prepareUserOperation",
  "params": [
    {
      "to": "0x0c54fccd2e384b4bb6f2e405bf5cbc15a017aafb",
      "value": "0x0",
      "data": "0x"
    },
    {
      "to": "0x660265edc169bab511a40c0e049cc1e33774443d",
      "value": "0x0",
      "data": "0x619a309f"
    }
  ]
}

eth_patchUserOperation​

Patches some allowed properties of a user operation.

Parameters​

An array containing:

  1. User operation object, which contains:
    • sender: string - Account making the operation.
    • callData: string - Data to pass to the sender during the main execution call.
    • initCode: string - Account bytecode (needed if and only if the account is not yet onchain and needs to be created).
    • nonce: string - Anti-replay parameter.
    • callGasLimit: string - Amount of gas to allocate to the main execution call.
    • verificationGasLimit: string - Amount of gas to allocate to the verification step.
    • preVerificationGas: string - Amount of gas to compensate the bundler for pre-verification execution, to pay for callData, and to account for overhead that can't be tracked onchain.
    • maxFeePerGas: string - Maximum total fee the sender is willing to pay per gas.
    • maxPriorityFeePerGas: string - Maximum fee the sender is willing to pay per gas above the base fee.
    • paymasterAndData: string - Address of the paymaster sponsoring the transaction, followed by extra data to send to the paymaster (empty for self-sponsored transactions).
    • signature: string - Data passed into the account along with the nonce during the verification step.

Returns​

A partial user operation object containing:

  • paymasterAndData: string - Address of the paymaster sponsoring the transaction, followed by extra data to send to the paymaster (empty for self-sponsored transactions).
  • callGasLimit: string - (Optional) Amount of gas to allocate to the main execution call.
  • verificationGasLimit: string - (Optional) Amount of gas to allocate to the verification step.
  • preVerificationGas: string - (Optional) Amount of gas to compensate the bundler for pre-verification execution, to pay for callData, and to account for overhead that can't be tracked onchain.

Example​

{
  "method": "eth_patchUserOperation",
  "params": [
    {
      "sender": "0x4584d2B4905087A100420AFfCe1b2d73fC69B8E4",
      "nonce": "0x1",
      "initCode": "0x",
      "callData": "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",
      "callGasLimit": "0x58a83",
      "verificationGasLimit": "0xe8c4",
      "preVerificationGas": "0xc57c",
      "maxFeePerGas": "0x87f0878c0",
      "maxPriorityFeePerGas": "0x1dcd6500",
      "paymasterAndData": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
      "signature": "0x000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"
    }
  ]
}

eth_signUserOperation​

Signs a user operation.

Parameters​

An array containing:

  1. User operation object, which contains:
    • sender: string - Account making the operation.
    • callData: string - Data to pass to the sender during the main execution call.
    • initCode: string - Account bytecode (needed if and only if the account is not yet onchain and needs to be created).
    • nonce: string - Anti-replay parameter.
    • callGasLimit: string - Amount of gas to allocate to the main execution call.
    • verificationGasLimit: string - Amount of gas to allocate to the verification step.
    • preVerificationGas: string - Amount of gas to compensate the bundler for pre-verification execution, to pay for callData, and to account for overhead that can't be tracked onchain.
    • maxFeePerGas: string - Maximum total fee the sender is willing to pay per gas.
    • maxPriorityFeePerGas: string - Maximum fee the sender is willing to pay per gas above the base fee.
    • paymasterAndData: string - Address of the paymaster sponsoring the transaction, followed by extra data to send to the paymaster (empty for self-sponsored transactions).
    • signature: string - Data passed into the account along with the nonce during the verification step.
  2. Entry point: string - Hash of the entry point contract.

Returns​

Signature: string - Hex-encoded signature.

Example​

{
  "method": "eth_signUserOperation",
  "params": [
    {
      "sender": "0x4584d2B4905087A100420AFfCe1b2d73fC69B8E4",
      "nonce": "0x1",
      "initCode": "0x",
      "callData": "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",
      "callGasLimit": "0x58a83",
      "verificationGasLimit": "0xe8c4",
      "preVerificationGas": "0xc57c",
      "maxFeePerGas": "0x87f0878c0",
      "maxPriorityFeePerGas": "0x1dcd6500",
      "paymasterAndData": "0x952514d7cBCB495EACeB86e02154921401dB0Cd9dac17f958d2ee523a2206206994597c13d831ec700000000000000000000000000000000000000000000000000000000779b3fbb00000000000000006565b267000000000000000000000000000000000000000029195b31a9b1c6ccdeff53e359ebbcd5f075a93c1aaed93302e5fde5faf8047028b296b8a3fa4e22b063af5069ae9f656736ffda0ee090c0311155722b905f781b",
      "signature": "0x"
    },
    "0x5FF137D4b0FDCD49DcA30c7CF57E578a026d2789"
  ]
}