@t402/evm-core

T402 EVM Core Types and Utilities - Zero external dependencies.

Overview

This package provides EVM types, constants, and utilities for the T402 payment protocol without requiring viem as a dependency. Use this package when you want to work with T402 EVM types without bundling the full viem library.

For full EVM functionality with viem integration, use @t402/evm instead.

Installation

npm install @t402/evm-core
# or
pnpm add @t402/evm-core

Usage

import {
  // Primitive types
  type Address,
  type Hex,
  bytesToHex,
  hexToBytes,

  // Payment types
  type ExactEIP3009Payload,
  type UptoEIP2612Payload,

  // Constants
  authorizationTypes,
  eip3009ABI,

  // Signer interfaces
  type ClientEvmSigner,
  type FacilitatorEvmSigner,

  // Token registry
  TOKEN_REGISTRY,
  getTokenConfig,
  getNetworkTokens,

  // Utilities
  createNonce,
  getEvmChainId,
} from "@t402/evm-core";

// Use types without viem
const payload: ExactEIP3009Payload = {
  authorization: {
    from: "0x...",
    to: "0x...",
    value: "1000000",
    validAfter: "0",
    validBefore: "1893456000",
    nonce: createNonce(),
  },
};

When to Use This Package

Use @t402/evm-core when:

• You only need types and don't need viem functionality
• You're building a type-only package that depends on T402 types
• You want to reduce bundle size by avoiding viem
• You're using a different EVM library (ethers.js, web3.js, etc.)

Use @t402/evm when:

• You need full EVM signing and verification
• You're using viem in your project
• You need the client or facilitator scheme implementations

Exports

Primitive Types

• Address - Ethereum address type (`0x${string}`)
• Hex - Hexadecimal string type
• Bytes32 - 32-byte hex value
• bytesToHex() - Convert Uint8Array to hex
• hexToBytes() - Convert hex to Uint8Array

Payment Types

• ExactEIP3009Payload - EIP-3009 TransferWithAuthorization payload
• ExactLegacyPayload - Legacy approve+transferFrom payload
• UptoEIP2612Payload - EIP-2612 Permit payload for metered payments
• PermitSignature - EIP-2612 signature components
• PermitAuthorization - EIP-2612 permit parameters

Constants

• authorizationTypes - EIP-712 type definitions for EIP-3009
• legacyAuthorizationTypes - EIP-712 type definitions for legacy flow
• eip3009ABI - ABI for EIP-3009 token contracts
• erc20LegacyABI - ABI for standard ERC-20 operations

Signer Interfaces

• ClientEvmSigner - Interface for client-side signing
• FacilitatorEvmSigner - Interface for facilitator operations
• toClientEvmSigner() - Convert to ClientEvmSigner
• toFacilitatorEvmSigner() - Convert to FacilitatorEvmSigner

Token Registry

• TOKEN_REGISTRY - Complete token configuration by network
• USDT0_ADDRESSES - USDT0 contract addresses
• USDC_ADDRESSES - USDC contract addresses
• getTokenConfig() - Get token config by network/symbol
• getNetworkTokens() - Get all tokens for a network
• getTokenByAddress() - Find token by contract address
• getEIP712Domain() - Get EIP-712 domain for token

Utilities

• createNonce() - Generate random 32-byte nonce
• getEvmChainId() - Get chain ID from network name

Related Packages

• @t402/core - Core protocol types and client
• @t402/evm - Full EVM mechanism with viem integration
• @t402/fetch - HTTP wrapper with automatic payment handling

License

Apache-2.0