README

Solidity ABI calldata encoder in pure PHP — byte-for-byte parity with ethers.js v6.

Encode Ethereum / EVM Solidity ABI calldata in pure PHP: function selectors (methodId), static head types (address, uint8 / uint24 / uint256) and top-level dynamic types (bytes, string). Output is byte-for-byte equivalent to ethers.js v6 Interface.encodeFunctionData, so calldata built in PHP matches what your JavaScript tooling and Solidity contracts expect.

Features

• Function selector (methodId) from a canonical signature via keccak-256.
• Full call encoding (selector + head + dynamic tail) in one call.
• Component encoders: encodeAddress, encodeUint, encodeBytes.
• Bigint-safe uint256 via ext-gmp — accepts hex or decimal strings, handles max uint256.
• Byte-for-byte parity with ethers.js v6 (cross-validated in tests).
• PHPStan level 9 clean, strict_types.

Why amashukov/abi-encoder-php

Most PHP web3 stacks pull in web3p/web3.php (and its web3p/ethereum-abi) for ABI encoding, which is a much larger surface than a contract call usually needs. This package is intentionally narrow and dependency-light: it covers the head-only static types and top-level dynamic bytes / string that real EVM contract calls use, with explicit ethers.js v6 parity as the correctness bar. If you only need to build calldata for eth_sendRawTransaction, this is the focused tool.

Installation

composer require amashukov/abi-encoder-php

Usage

Function selector

use Amashukov\AbiEncoder\AbiEncoder;

AbiEncoder::methodId('withdraw(address,uint256)');   // 'f3fef3a3'

The selector is the first 4 bytes of the keccak-256 hash of the canonical signature, returned as 8 hex chars (no 0x).

Encode a full call

$calldata = AbiEncoder::encodeCall('withdraw(address,uint256)', [
    ['address', '0x1234567890123456789012345678901234567890'],
    ['uint256', '500000000000000000'],   // decimal string; bigints supported via ext-gmp
]);
// 0xf3fef3a3000000…0006f05b59d3b20000

Each argument is a [type, value] pair. Supported types: address, uint8, uint24, uint256, bytes, string. Dynamic types (bytes, string) are placed in the tail with the correct head offset, exactly as the ABI spec + ethers.js produce.

Encode individual components

AbiEncoder::encodeAddress('0xABCDEF…');         // left-padded to 32 bytes, lowercased
AbiEncoder::encodeUint('0xFF');                 // accepts hex or decimal; bigint-safe
AbiEncoder::encodeUint('115792089237316195423570985008687907853269984665640564039457584007913129639935'); // max uint256
AbiEncoder::encodeBytes('0xdeadbeef');          // length word + right-padded data
AbiEncoder::encodeBytes('v1', isString: true);  // UTF-8 string as dynamic bytes

Scope

Intentionally narrow — covers the head-only static types and top-level dynamic bytes / string that real EVM contract calls use. Nested dynamic types (bytes[], string[], dynamic tuples) are out of scope.

Requirements

• PHP 8.3+
• ext-gmp
• amashukov/keccak-php (for the selector hash)

Related packages

Quality

• PHPStan level 9.
• php-cs-fixer with the @PER-CS ruleset.
• GitHub Actions CI on every push.
• Byte-for-byte parity tests against ethers.js v6 Interface.encodeFunctionData.

License

MIT.