Gas Golf Diff Comparator Between Implementations

WHAT IT DOES

Gas Golf Diff Comparator Between Implementations is a read-only developer tool that compares the gas efficiency of two contract implementations side-by-side. It analyzes bytecode to estimate gas costs based on opcode patterns, compares bytecode sizes, extracts and compares function selectors, and breaks down opcode usage (SLOAD, SSTORE, CALL, etc.) between versions. The tool provides a clear visual comparison of gas estimates, bytecode size differences, function-level changes (added, removed, unchanged), and an overall improvement assessment. It helps developers validate that gas optimization efforts (gas golfing) actually result in measurable improvements, identify regressions, and quantify savings before deployment.

HOW TO USE

Connect your EVM-compatible wallet via the BGWallet bridge and select the network where both contracts are deployed. Enter the original (baseline) contract address and the optimized (gas-golfed) contract address, then click "Compare Gas Golf Diff". The tool fetches bytecode for both contracts, performs static analysis including opcode counting, gas estimation based on EVM operation costs, selector extraction, and function change detection. Results include a gas estimate comparison with percentage improvement, bytecode size diff, opcode breakdown table, function selector changes (added/removed/unchanged), and a visual bar chart comparing gas estimates. All analysis is read-only—no signatures or transactions are submitted.

TECHNICAL MECHANISM

The tool uses ethers.js v5.7.2 to fetch contract bytecode from both addresses via provider.getCode(address), then performs multi-faceted static analysis. For gas estimation, it scans bytecode hex strings for key EVM opcodes: SLOAD (0x54) at 100 gas each, SSTORE (0x55) at 2000 gas each, CALL (0x73) at 700 gas each, MLOAD (0x51) at 3 gas, MSTORE (0x52) at 3 gas, ADD/MUL (0x01,0x02) at 3 gas, and JUMP/JUMPI (0x56,0x57) at 10 gas each, plus a base cost of 21000 gas per transaction and a storage cost of 200 gas per byte of deployment bytecode. Bytecode size is calculated by converting to hex and dividing by 2. Function selectors are extracted using the PUSH4 opcode pattern (0x63) to identify all 4-byte identifiers. The tool compares selector sets to compute a Jaccard similarity score and identify added, removed, and unchanged functions. Opcode counts are computed for SLOAD, SSTORE, and CALL operations to provide granular insights into where gas savings may have come from. All estimates are static and deterministic, enabling consistent comparison across runs without requiring on-chain transaction execution.

WHAT IT CANNOT SEE

This tool has fundamental limitations that users must understand. It cannot simulate or estimate gas savings without executing actual transactions—the estimates are based on static bytecode analysis and do not account for runtime execution paths, conditional logic, or loops. It cannot account for runtime state differences that affect gas costs, such as storage values (cold vs warm slots), balances, slot packing, or the current state of the EVM environment. It cannot compare gas usage across different compilers or optimization settings—differences in solc version or optimizer settings can drastically change bytecode structure and gas costs, making direct comparisons misleading. It cannot predict gas cost differences for functions that require specific execution paths or state conditions not present in historical data—unusual code paths or edge cases may have very different gas profiles than the common paths analyzed statically. It cannot account for dynamic gas costs such as calldata costs, memory expansion costs, or log costs that depend on runtime input sizes. It cannot detect gas savings that come from reduced calldata size (when comparing function signatures or parameter packing). The tool's gas estimates are approximations and should be validated with actual transaction simulations or mainnet execution data. It cannot analyze contracts that are not deployed or that have no bytecode.

PLEASE NOTE

This tool only supports EVM-compatible blockchains (Ethereum, Polygon, BSC, Avalanche C-Chain, Optimism, Arbitrum, and their testnets). Solana, Tron, Starknet, SUI, TON, Aptos, Bitcoin, Cosmos, and XRP are not supported. The tool is free, open-source, requires no API keys, and uses the wallet's native provider for all read operations. Gas estimates are approximate and should be validated with actual simulation tools like Tenderly, Hardhat, or Foundry before relying on them for production decisions.