Exploring Blockchain Data

Overview

Query and analyze blockchain data across multiple EVM-compatible networks including Ethereum, Polygon, Arbitrum, Optimism, and BSC. Supports transaction lookups, address balance checks, block inspection, token balance queries, transaction history retrieval, and whale wallet tracking via a unified CLI.

Prerequisites

• Python 3.8+ with requests and web3 libraries installed (pip install requests web3 )

• Etherscan API key (free tier provides 5 requests/second; set via ETHERSCAN_API_KEY environment variable)

• Optional: API keys for Polygonscan, Arbiscan, and other chain-specific explorers for higher rate limits

• blockchain_explorer.py CLI script, chain_client.py , and token_resolver.py modules available in the plugin directory

• RPC endpoint access (public endpoints work; dedicated providers like Alchemy, Infura, Chainstack, or QuickNode recommended for reliability)

Instructions

• Set the Etherscan API key as an environment variable: export ETHERSCAN_API_KEY=<key> to unlock higher rate limits beyond the default 5 requests/second.

• Run python blockchain_explorer.py tx <hash> to look up a transaction by hash, returning status, block number, from/to addresses, value transferred, and gas details.

• Append --detailed to the transaction query to decode the function call, identify the interacting protocol, and display input parameters.

• Specify --chain polygon , --chain arbitrum , or --chain bsc to query transactions on alternative EVM chains when the hash is not found on Ethereum.

• Run python blockchain_explorer.py address <address> to check the native token balance and total transaction count for a wallet.

• Add --history --limit 50 to the address query to retrieve the most recent 50 transactions with timestamps, values, and counterparties.

• Add --tokens to the address query to list all ERC-20 token holdings with balances, symbols, and USD values via CoinGecko price resolution.

• Run python blockchain_explorer.py block latest to inspect the most recent block, or python blockchain_explorer.py block <number> for a specific block.

• Run python blockchain_explorer.py token <wallet> <contract> to check the balance of a specific ERC-20 token at a wallet address, with automatic decimal and symbol resolution.

• Export any query result in JSON or CSV format using --format json or --format csv and redirect to a file for downstream processing.

• Enable verbose mode with --verbose to display API request URLs, response times, cache hit/miss status, and rate limit counters for debugging.

See ${CLAUDE_SKILL_DIR}/references/implementation.md for the full four-step implementation workflow.

Output

• Transaction detail tables showing hash, chain, status, block number, from/to addresses, value, gas price (Gwei), gas limit, gas used, and gas cost

• Decoded transaction data with function name, protocol identification, and parsed input parameters (when --detailed is used)

• Address summary with native balance, transaction count, and explorer link

• Transaction history tables with timestamp, hash, from/to, value, and direction (in/out)

• Token balance listings with contract address, token name, symbol, raw balance, human-readable balance, and USD value

• Block details with block number, timestamp, transaction count, gas used, and miner/validator

• JSON (output.json ) or CSV (transactions.csv ) export files for programmatic consumption

Error Handling

Error Cause Solution

Transaction not found

Transaction pending in mempool, wrong chain selected, or invalid hash Wait and retry for pending transactions; try --chain polygon , --chain arbitrum , --chain bsc ; verify hash is 66 characters starting with 0x

Explorer API error: Max rate limit reached

Too many requests; no API key or quota exhausted Wait 1-5 seconds and retry; set ETHERSCAN_API_KEY for higher limits; upgrade to paid tier for production use

RPC error: execution timeout

RPC endpoint overloaded or complex query timed out Retry with a different RPC endpoint; use a dedicated provider (Alchemy, Infura, QuickNode); simplify the query

Invalid address: 0xinvalid

Address has wrong length, invalid checksum, or non-hex characters Verify 42 characters with 0x prefix; use the checksummed version from a block explorer; convert to lowercase if checksum fails

Contract source code not verified

Contract source not published on the explorer Use known function signature databases for decoding; check if the contract is a proxy and look up the implementation address

Token: ??? (Unknown Token)

Token too new, too obscure, or not tracked by CoinGecko Check the token contract directly on the explorer; look up on a DEX (Uniswap, SushiSwap); manually specify decimals if known

Price: N/A

Token not listed on CoinGecko, API rate limited, or very low liquidity Check the DEX for on-chain price; use an alternative price feed; calculate from LP reserves

ImportError: No module named 'requests'

Missing Python dependencies Run pip install requests web3 to install required packages

Examples

Look Up a Transaction Across Chains

Try Ethereum first, then Polygon if not found

python blockchain_explorer.py tx 0x1234...abcdef --chain ethereum python blockchain_explorer.py tx 0x1234...abcdef --chain polygon

Returns a formatted table with transaction status, block number, value transferred, gas details, and a link to the block explorer. Adding --detailed decodes the function call (e.g., swapExactTokensForTokens on Uniswap).

Full Wallet Analysis

python blockchain_explorer.py address 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 --history --tokens --limit 50

Produces a wallet summary (ETH balance, total transaction count), the 50 most recent transactions with timestamps and counterparties, and a complete ERC-20 token holdings list with USD values. Useful for whale watching or due diligence on a wallet.

Check USDC Balance and Export to JSON

python blockchain_explorer.py token 0xYourWallet 0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48 --format json > usdc_balance.json

Resolves the USDC contract, fetches the wallet balance with proper decimal handling (6 decimals for USDC), includes the current USD price, and writes the result to usdc_balance.json for integration with dashboards or alerting pipelines.

Resources

• Etherscan API Documentation -- primary explorer API for Ethereum; free tier available with registration

• CoinGecko API -- token price resolution and metadata lookup

• web3.py Documentation -- Python library for direct RPC interaction with EVM chains

• Alchemy / Infura / QuickNode -- dedicated RPC providers for reliable node access

• 4byte.directory -- function signature database for decoding unverified contract interactions