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Paymaster

Paymaster is a branded Address type representing an ERC-4337 paymaster contract. Paymasters sponsor gas fees for user operations, enabling gasless transactions or allowing users to pay gas in ERC-20 tokens.

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Quick Start

import { Paymaster } from '@tevm/voltaire/primitives/Paymaster';

// Create paymaster address
const paymaster = Paymaster.from("0x742d35Cc6634C0532925a3b844Bc9e7595f251e3");

// Convert to hex
console.log(Paymaster.toHex(paymaster));
// "0x742d35cc6634c0532925a3b844bc9e7595f251e3"

// Compare addresses
const same = Paymaster.equals(paymaster, "0x742d35Cc...");

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Type Definition

import type { AddressType } from '../Address/AddressType.js';
import type { brand } from '../../brand.js';

export type PaymasterType = AddressType & { readonly [brand]: "Paymaster" };

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API Reference

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from

Create Paymaster from address input. 
function from(
  value: number | bigint | string | Uint8Array | AddressType
): PaymasterType

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toHex

Convert Paymaster to hex string. 
function toHex(
  paymaster: number | bigint | string | Uint8Array | AddressType
): string

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equals

Check if two Paymaster addresses are equal. 
function equals(
  paymaster1: number | bigint | string | Uint8Array | AddressType,
  paymaster2: number | bigint | string | Uint8Array | AddressType
): boolean

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Paymaster Functionality

Paymasters enable:
  1. Gasless transactions: Sponsor user gas fees completely
  2. Token payment: Users pay gas in ERC-20 tokens
  3. Conditional sponsorship: Rules-based gas sponsorship
  4. Rate limiting: Control spending per account/time period

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Usage with User Operations

import { UserOperation } from '@tevm/voltaire/primitives/UserOperation';
import { Paymaster } from '@tevm/voltaire/primitives/Paymaster';

const paymasterAddr = Paymaster.from("0x742d35Cc6634C0532925a3b844Bc9e7595f251e3");

// paymasterAndData format: paymaster (20 bytes) + paymasterData (variable)
const paymasterAndData = new Uint8Array([
  ...paymasterAddr,
  // ...paymasterData (paymaster-specific data)
]);

const userOp = UserOperation.from({
  sender: "0x...",
  nonce: 0n,
  // ... other fields
  paymasterAndData,
  signature: "0x",
});

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References