Contract ABI Sync Tool for Frontend Repos

WHAT IT DOES

This tool helps frontend developers keep their contract ABIs in sync with deployed contracts. Given a contract address and its ABI (typically copied from Etherscan or your project's artifacts), it verifies that the contract exists on the selected chain, performs a heuristic proxy detection (EIP-1967 implementation slot), and then packages the ABI into a clean, downloadable JSON file ready for your frontend repository. It also provides a preview of the ABI and shows a snippet of the on-chain bytecode to confirm the contract is deployed. This eliminates manual copy-paste errors and gives you confidence that the ABI you're shipping matches the contract you're targeting.

HOW TO USE

Connect your wallet via the BGWallet bridge — this provides the RPC endpoint for on-chain reads. Select the network where your contract is deployed. Enter the contract address and paste the contract's ABI as a JSON array (you can obtain this from Etherscan's "Contract" tab, or from your Hardhat/Truffle artifacts). Click "Sync & generate ABI file". The tool fetches the bytecode to confirm the contract exists, checks the implementation slot for proxy patterns, and validates that your ABI is properly formatted JSON. If everything checks out, you'll see a summary of the contract status, proxy detection results, and a preview of the ABI. A "Download ABI" button lets you save the JSON file directly to your local machine — ready to drop into your frontend repo's src/abis/ folder.

ONE TECHNICAL SECTION

The tool uses eth_getCode to verify that a contract exists at the provided address. For proxy detection, it reads the EIP-1967 implementation storage slot (0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc) using eth_getStorageAt — if the slot contains a non-zero address, the tool flags the contract as a proxy and displays the implementation address. The ABI validation is performed client-side using JSON.parse, with additional checks to ensure the parsed value is an array and each entry has a type field. The tool does not compile source or perform bytecode comparison; it relies on the user to provide the correct ABI. The download functionality uses a Blob and a temporary anchor element to trigger a browser download, producing a properly formatted JSON file with the ABI array.

WHAT IT CANNOT SEE

This tool cannot verify that the provided ABI actually matches the on-chain bytecode beyond basic existence checks — it does not perform function signature matching or bytecode comparison. It cannot detect runtime code changes in proxies without resolving the implementation address and checking it separately. It cannot generate an ABI from bytecode alone; you must provide the ABI manually or obtain it from a verified source. It cannot detect upgradeable proxy patterns beyond the EIP-1967 slot (e.g., Beacon proxies, diamond proxies, or custom implementations) without additional configuration. It also cannot read state variables, events, or historical transaction data — it is purely a verification and packaging tool for ABIs.

PLEASE NOTE

This tool works exclusively on EVM-compatible chains. The ABI must be a valid JSON array conforming to the Ethereum ABI specification. If the contract is a proxy, you should ensure the ABI corresponds to the implementation contract, not the proxy itself. The tool is read-only and does not sign or send any transactions. It is designed for frontend developers and DevOps workflows — always double-check the ABI against the actual contract source, especially for critical or high-value contracts.