Optimistic Rollup Challenger

WHAT IT DOES

This tool provides read-only access to optimistic rollup challenge and dispute data on EVM chains. It allows security researchers, auditors, and developers to inspect rollup contract state, output roots, fraud proof windows, challenged batches, and dispute game events. Instead of relying on block explorers or third-party dashboards, you connect directly to the blockchain via your wallet's RPC provider and retrieve raw rollup data. You can check the latest output index, view recent output roots, see which outputs have been challenged, and monitor fraud proof submission events. The tool is designed for optimistic rollup security analysis and research.

HOW TO USE

Connect your wallet using the BGWallet bridge and select your target network (Optimism, Arbitrum, or other rollup-compatible chains). Choose the query type: Rollup contract state, Batch commitment & output root, Challenge/dispute events, or Fraud proof window. Enter the rollup contract address. For batch queries, optionally enter a batch ID to check a specific output root and its challenge status. For fraud proof window queries, optionally enter an output index to check if it is within the challenge window. Click "Query challenge data" to execute the query. Results appear in the results panel with formatted JSON output.

TECHNICAL MECHANISM

The tool uses ethers.js v5.7.2 to interact with the blockchain via BGWallet's provider. For rollup state queries, it calls common rollup contract methods: latestOutputIndex(), outputRoots(), challengedOutputs(), fraudProofWindow(), owner(), and totalBatches(). For batch queries, it retrieves specific output roots and their challenge status using outputRoots() and challengedOutputs(). For challenge events, it uses eth_getLogs with automatic chunking and halving on limit errors, searching for OutputProposed, OutputChallenged, OutputConfirmed, and FraudProofSubmitted events. For fraud proof window queries, it reads the fraudProofWindow() value and calculates the window start block relative to the current block. All BigNumber values are converted to strings for readable output.

WHAT IT CANNOT SEE

This tool cannot initiate on-chain challenges — it is read-only only. It cannot verify the correctness of state transitions without full node execution, which would require running an L2 node and replaying all transactions. It cannot detect fraud that is not visible in the on-chain data — if a batch is invalid but never challenged, the tool will not flag it. It cannot prove that a batch is invalid without executing the transactions and comparing the resulting state root. It cannot determine if fraud proofs would succeed without specialized verification logic that implements the rollup's fraud proof mechanism. It cannot detect off-chain activity, sequencer censorship, or transactions that were never submitted on-chain. You are responsible for understanding the rollup's security model and verifying its trust assumptions.

PLEASE NOTE

EVM chains only. Supports Optimism, Arbitrum, and other optimistic rollups with standard challenge contracts. Does not support Solana, Tron, Starknet (non-EVM), SUI, TON, Aptos, Bitcoin, Cosmos, or XRP. Requires a wallet connected via BGWallet to provide the RPC provider. The tool is read-only and does not sign any transactions. Always verify contract addresses and challenge data independently before relying on the results.