---
description: Generates a ready-to-sign EIP-712 digest from JSON typed data
---

## `eip712HashTypedData`

### Signature

```solidity
function eip712HashTypedData(string calldata jsonData) external pure returns (bytes32 digest);
```

### Description

Generates the final, ready-to-sign [EIP-712](https://eips.ethereum.org/EIPS/eip-712) digest (`keccak256("\x19\x01" ‖ domainSeparator ‖ hashStruct(message))`) from a JSON document in the standard `eth_signTypedData_v4` format with `types`, `primaryType`, `domain`, and `message` fields.

This matches what wallets sign, so it is useful for verifying a contract's full typed-data flow, including the domain separator, against a single fixture.

### Parameters

| Parameter  | Type     | Description                                        |
|------------|----------|----------------------------------------------------|
| `jsonData` | `string` | The typed data as `eth_signTypedData_v4` style JSON |

### Returns

| Type      | Description                  |
|-----------|------------------------------|
| `bytes32` | The EIP-712 signing digest   |

### Examples

```solidity [test/Eip712HashTypedData.t.sol]
function testHashTypedData() public view {
    string memory jsonData =
        '{"types":{"EIP712Domain":[{"name":"name","type":"string"},{"name":"version","type":"string"},{"name":"chainId","type":"uint256"},{"name":"verifyingContract","type":"address"},{"name":"salt","type":"bytes32"}]},"primaryType":"EIP712Domain","domain":{"name":"example.metamask.io","version":"1","chainId":1,"verifyingContract":"0x0000000000000000000000000000000000000000"},"message":{}}';

    bytes32 expected = hex"122d1c8ef94b76dad44dcb03fa772361e20855c63311a15d5afe02d1b38f6077";
    assertEq(vm.eip712HashTypedData(jsonData), expected);
}
```

### Related Cheatcodes

- [`eip712HashStruct`](/reference/cheatcodes/eip712-hash-struct) - Hash a single struct value
- [`eip712HashType`](/reference/cheatcodes/eip712-hash-type) - Hash a type definition
- [`sign`](/reference/cheatcodes/sign) - Sign the resulting digest
