> ## Documentation Index
> Fetch the complete documentation index at: https://voltaire.tevm.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# ERC-6093 Standard Token Errors

> Custom errors for ERC-20, ERC-721, and ERC-1155 tokens

Standardized error definitions for token contracts implementing ERC-20, ERC-721, and ERC-1155.

<Tip title="ERC Reference">
  Implements [ERC-6093](https://eips.ethereum.org/EIPS/eip-6093) custom errors for common token operations.
</Tip>

## Overview

ERC-6093 defines standard custom errors for token contracts, replacing generic `require` messages with structured errors containing relevant context. Benefits:

* Gas efficiency (custom errors cheaper than strings)
* Type-safe error handling
* Standardized error names across implementations
* Rich context for debugging

## ERC-20 Errors

```typescript theme={null}
import {
  ERC20InsufficientBalance,
  ERC20InvalidSender,
  ERC20InvalidReceiver,
  ERC20InsufficientAllowance,
  ERC20InvalidApprover,
  ERC20InvalidSpender
} from '@tevm/voltaire/Abi/error/standards';
```

### ERC20InsufficientBalance

```solidity theme={null}
error ERC20InsufficientBalance(address sender, uint256 balance, uint256 needed)
```

Thrown when transfer amount exceeds sender's balance.

**Example:**

```typescript theme={null}
import { ERC20InsufficientBalance } from '@tevm/voltaire/Abi/error/standards';
import { encodeParams } from '@tevm/voltaire/Abi/error';

const error = encodeParams(ERC20InsufficientBalance, {
  sender: '0x1234...',
  balance: 100n,
  needed: 150n
});
```

### ERC20InsufficientAllowance

```solidity theme={null}
error ERC20InsufficientAllowance(address spender, uint256 allowance, uint256 needed)
```

Thrown when `transferFrom` amount exceeds allowance.

### ERC20InvalidSender / Receiver / Approver / Spender

```solidity theme={null}
error ERC20InvalidSender(address sender)
error ERC20InvalidReceiver(address receiver)
error ERC20InvalidApprover(address approver)
error ERC20InvalidSpender(address spender)
```

Thrown for zero address or other invalid addresses.

## ERC-721 Errors

```typescript theme={null}
import {
  ERC721InvalidOwner,
  ERC721NonexistentToken,
  ERC721IncorrectOwner,
  ERC721InvalidSender,
  ERC721InvalidReceiver,
  ERC721InsufficientApproval,
  ERC721InvalidApprover,
  ERC721InvalidOperator
} from '@tevm/voltaire/Abi/error/standards';
```

### ERC721NonexistentToken

```solidity theme={null}
error ERC721NonexistentToken(uint256 tokenId)
```

Token doesn't exist.

### ERC721IncorrectOwner

```solidity theme={null}
error ERC721IncorrectOwner(address sender, uint256 tokenId, address owner)
```

Sender is not token owner.

### ERC721InsufficientApproval

```solidity theme={null}
error ERC721InsufficientApproval(address operator, uint256 tokenId)
```

Operator not approved for token.

## ERC-1155 Errors

```typescript theme={null}
import {
  ERC1155InsufficientBalance,
  ERC1155InvalidSender,
  ERC1155InvalidReceiver,
  ERC1155MissingApprovalForAll,
  ERC1155InvalidApprover,
  ERC1155InvalidOperator,
  ERC1155InvalidArrayLength
} from '@tevm/voltaire/Abi/error/standards';
```

### ERC1155InsufficientBalance

```solidity theme={null}
error ERC1155InsufficientBalance(address sender, uint256 balance, uint256 needed, uint256 tokenId)
```

Insufficient balance for token ID.

### ERC1155InvalidArrayLength

```solidity theme={null}
error ERC1155InvalidArrayLength(uint256 idsLength, uint256 valuesLength)
```

Mismatch between ids and values array lengths in batch operations.

### ERC1155MissingApprovalForAll

```solidity theme={null}
error ERC1155MissingApprovalForAll(address operator, address owner)
```

Operator not approved for all tokens.

## Usage Patterns

### Decoding Errors

```typescript theme={null}
import { decodeParams } from '@tevm/voltaire/Abi/error';
import { ERC20InsufficientBalance } from '@tevm/voltaire/Abi/error/standards';

try {
  await token.transfer(recipient, amount);
} catch (err) {
  if (err.data) {
    const decoded = decodeParams(ERC20InsufficientBalance, err.data);
    console.log(`Insufficient balance: has ${decoded.balance}, needs ${decoded.needed}`);
  }
}
```

### Encoding for Testing

```typescript theme={null}
import { encodeParams, getSelector } from '@tevm/voltaire/Abi/error';
import { ERC721NonexistentToken } from '@tevm/voltaire/Abi/error/standards';

// Encode error for mock contract
const errorData = Buffer.concat([
  getSelector(ERC721NonexistentToken),
  encodeParams(ERC721NonexistentToken, { tokenId: 999n })
]);

// Use in test revert expectation
await expect(contract.ownerOf(999)).rejects.toThrow(errorData);
```

## Specification

**Defined in:** [src/primitives/Abi/error/standards/](https://github.com/evmts/voltaire/blob/main/src/primitives/Abi/error/standards/)

**See also:**

* [ERC-6093 Specification](https://eips.ethereum.org/EIPS/eip-6093)
* [Error Encoding/Decoding](/primitives/abi/error)