Multi-chain Explorer API

Query Etherscan-compatible block explorer APIs for transaction history, contract source code, ABIs, and gas data.

Supported Explorers

Chain	Base URL	Env Var (optional override)
Ethereum	`https://api.etherscan.io/api`	`ETHERSCAN_API_KEY`
BSC	`https://api.bscscan.com/api`	`BSCSCAN_API_KEY` or same key
Polygon	`https://api.polygonscan.com/api`	`POLYGONSCAN_API_KEY`
Arbitrum	`https://api.arbiscan.io/api`	`ARBISCAN_API_KEY`
Optimism	`https://api-optimistic.etherscan.io/api`	`OPTIMISM_API_KEY`
Base	`https://api.basescan.org/api`	`BASESCAN_API_KEY`

All explorers accept the apikey parameter. Many share a single Etherscan key, but some chains require separate registration.

Rate limit: 5 calls/second per key.

Modules & Actions

Account — Transaction History

?module=account&action=txlist&address={addr}&startblock=0&endblock=99999999&page=1&offset=20&sort=desc&apikey={key}

Returns normal transactions for an address.

Account — Token Transfers (ERC-20)

?module=account&action=tokentx&address={addr}&page=1&offset=20&sort=desc&apikey={key}

Filter by contract: add &contractaddress={token}

Account — ERC-721 Transfers

?module=account&action=tokennfttx&address={addr}&page=1&offset=20&sort=desc&apikey={key}

Account — Balance

?module=account&action=balance&address={addr}&tag=latest&apikey={key}

Returns balance in wei. Divide by 1e18 for ETH/BNB.

Contract — Get ABI

?module=contract&action=getabi&address={addr}&apikey={key}

Returns the contract ABI as a JSON string. Tip: Parse the result and pass it to read_contract or write_contract for dynamic contract interaction.

Contract — Get Source Code

?module=contract&action=getsourcecode&address={addr}&apikey={key}

Returns source code, compiler version, constructor arguments, and proxy implementation address if applicable.

Gas Tracker (Ethereum only)

?module=gastracker&action=gasoracle&apikey={key}

Returns SafeGasPrice, ProposeGasPrice, FastGasPrice in gwei.

Workflow: Dynamic Contract Interaction

User provides a contract address
Call getabi to fetch the ABI
Parse the ABI to list available read/write functions
Use read_contract with the ABI and function name to query
Use write_contract for state-changing calls (with user confirmation)

This enables interacting with ANY verified contract without pre-built tools.

Usage Notes

Always include &apikey={key} — requests without it are heavily rate-limited
Use offset and page for pagination; don't fetch more than needed
The getabi endpoint only works for verified contracts
For proxy contracts, getsourcecode includes the implementation address — fetch that ABI too
Cross-reference contract data with security-check skill for risk assessment

Example Queries

User: "Show my recent transactions on BSC" → Call BSCScan txlist for active wallet, present last 10 with value and status

User: "Get the ABI for this contract: 0x..." → Call getabi, parse result, summarize available functions

User: "What's the current gas price on Ethereum?" → Call gasoracle, present safe/standard/fast prices

etherscan