Blockchain Indexer

WHAT IT DOES

Blockchain Indexer lets you index and decode multiple event types from any contract across a specified block range. You provide the contract address, one or more event signatures (e.g., Transfer, Approval), and a block range, and the tool queries the chain for all matching logs, decodes them, and presents a structured index of the data. It automatically handles RPC block range limits by chunking requests and halving chunk size on failure (PLAYBOOK-C §5.1). The indexed data is grouped by event type and displayed in a clean table with links to block explorers. This is essential for developers building analytics dashboards, auditing contract activity, tracking token movements, monitoring governance votes, or analyzing any on-chain data patterns. It reads the current network chain ID from your wallet provider to ensure queries are directed to the correct network.

HOW TO USE

Connect your wallet using the "Connect" button (required for RPC access). Select the target network (Ethereum Mainnet, Sepolia, Polygon, BSC, Arbitrum, Optimism, and testnets are supported). Enter the contract address and one or more event signatures (one per line). Optionally, specify a block range — if left blank, the tool scans the most recent 10,000 blocks. Click "Index events" — the tool will fetch and decode all matching logs. Results are shown in a table with block numbers, transaction hashes, event names, and decoded data. The entire operation is read-only — no transactions are signed or sent.

TECHNICAL MECHANISM

The tool builds an ethers.js Interface from the provided event signatures and computes the Keccak-256 hash (topic0) for each event. It then uses eth_getLogs with a filter for the contract address and all event topics. Because public RPC providers cap the block range per request (often 10,000 blocks), the tool automatically chunks the requested range into smaller segments. If a chunk fails due to range limits, it halves the chunk size and retries, backing off until successful (PLAYBOOK-C §5.1). This ensures the scan completes even on restrictive RPCs. Once logs are fetched, the tool decodes each log using the Interface, parsing both indexed parameters (topics) and non-indexed parameters (data). The decoded events are grouped by event name and displayed with transaction and block links. The tool uses ethers.js v5.7.2 and the wallet's provider for all chain interactions.

WHAT IT CANNOT SEE

The tool cannot verify the correctness of the ABI or event signatures — incorrect signatures will result in no data or garbled decoding. It cannot handle complex nested types or dynamic arrays reliably without full ABI parsing (e.g., arrays of structs, nested tuples). It is limited by RPC provider rate limits and eth_getLogs block range caps — very large ranges may be slow or fail on free RPCs. It cannot index real-time events or maintain persistent state — each query is a fresh scan of historical logs. It cannot detect events from non-indexed parameters efficiently, as filtering only works on indexed topics. It cannot index events from contracts that do not emit standard logs.

PLEASE NOTE

This tool is for educational and analytical purposes. For production-grade indexing, consider using dedicated services like The Graph or hosted indexers. The accuracy of the results depends on the correctness of the event signatures. Always verify the signatures against the contract's ABI. The tool does not persist any data; all state is lost on page reload. EVM chains only.