Light Client Proof Verifier

WHAT IT DOES

Light Client Proof Verifier is a read-only developer tool that simulates the verification of Merkle proofs against EVM block state roots. It fetches block headers and state data (account balance, storage values, contract code) for a given block number and account address, simulates proof verification, and provides a comprehensive verification report. The tool validates account existence, retrieves storage values when keys are provided, matches expected values against actual state, and displays the Merkle proof structure. It helps developers understand how light client proofs work, test proof verification logic, and verify state inclusion without running a full node—essential for building light clients, cross-chain bridges, and trust-minimized applications.

HOW TO USE

Connect your EVM-compatible wallet via the BGWallet bridge and select the network you are targeting. Enter a block number, an account address, optionally a storage key (32-byte hex), and an expected value to verify. Click "Verify Proof" to simulate proof verification. The tool fetches the block header, retrieves account balance and code, and if a storage key is provided, fetches the storage value at that key. Results include block hash, account existence status, balance, storage value, expected value match, and a formatted Merkle proof structure. The tool provides a detailed verification summary with color-coded status indicators. All analysis is read-only—no signatures or transactions are submitted.

TECHNICAL MECHANISM

The tool uses ethers.js v5.7.2 to fetch block data via provider.getBlock(blockNumber), account state via provider.getBalance(account, blockNumber) and provider.getCode(account, blockNumber), and storage values via provider.getStorageAt(account, key, blockNumber). For each request, the block number is specified to query historical state—this is the foundation of light client verification. The tool constructs a simulated Merkle proof structure based on the retrieved data, including account proof, storage proof, and block state root. Verification is simulated by confirming that the account exists and that any provided storage key and expected value match the on-chain state. The tool outputs the full proof data in a formatted display, showing the account proof, storage proof, and block state root for reference. This simulation mirrors the actual proof verification process used in light clients, where a block header's state root is used to validate account and storage inclusion via Merkle Patricia proofs. The tool does not perform cryptographic verification of individual proof nodes—it validates the data consistency at the application level.

WHAT IT CANNOT SEE

This tool has fundamental limitations that users must understand. It cannot generate or create proofs—the tool only verifies existing state data and simulates proof structures, it does not produce proofs from external sources. It cannot validate proofs that use non-standard tree structures or alternative hashing algorithms—the tool is designed for Ethereum's Merkle Patricia tree format. It cannot verify proofs for chains that do not expose proof-generation APIs—the tool relies on standard eth_getProof and related methods. It cannot prove the absence of data (e.g., proving that a transaction was NOT included) without specialized proofs—only inclusion proofs are supported. It cannot verify proofs that span multiple block headers or require historical state queries beyond the requested block—verification is limited to a single block. It cannot validate proof data against incorrect block hashes without user input—the tool assumes the block number provided is correct. It cannot verify transaction receipt proofs—only account and storage proofs are supported. The tool's proof verification is simulated and does not perform actual Merkle path hashing or trie traversal.

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. Proof verification is simulated for demonstration purposes—real proof verification requires full cryptographic validation.