Onchain-testnet

Use when you need what a wallet or contract holds: reads the native ETH balance and ERC-20 balances (a default set of major tokens, or up to 20 token symbols/addresses you pass) for one address on Base or Ethereum in a single multicall, with human-readable amounts and USD values from Chainlink feeds, plus a total. Zero balances are omitted unless asked.

Use when a token has no Chainlink feed (long-tail, new or memecoins) and you need its current market price: finds every Uniswap v3 pool of the token against WETH, USDC (and USDT on Ethereum) across fee tiers, reads each pool's price (slot0) and reserves in one multicall, converts to USD with Chainlink, and returns the price from the deepest pool plus all pools with their depth. Flags thin liquidity. Uniswap v3 only (Aerodrome and other DEXs not included).

Use when you need who holds a token (concentration, whales, treasury): returns the top N holders of an ERC-20 contract on Base or Ethereum with rank, checksummed address, raw and formatted balance, and share of total supply when the explorer provides it. Public name tags and ENS from the explorer are included as labels; no personal identity is invented and emails are stripped. Ethereum prefers Blockscout, falls back to Ethplorer. Base uses Blockscout; if that explorer blocks the request, the cal

Use when you need a trustworthy USD price for crypto assets (ETH, BTC, cbBTC, SOL, LINK, AAVE, stablecoins), fiat FX rates (EUR, GBP, JPY…) or metals (XAU, XAG): reads the Chainlink price feed contracts directly from Base or Ethereum in one multicall and returns price, last update time, age in seconds, a stale flag and the feed address so the value is verifiable on-chain. Up to 10 symbols per call.

Use when you need to confirm or explain a transaction (e.g. verify a payment arrived): fetches the transaction, its receipt and block from Base or Ethereum and returns success/failed/pending, confirmations, timestamp, from, to, native value, gas used and fee, the 4-byte method selector, contract created, and every ERC-20 Transfer log decoded with token symbol and human amount. 404 (not charged) if the hash is unknown.

Use before sending funds or when you only have a human-readable name: resolves ENS names (.eth and DNS names on ENS, including offchain/wildcard resolvers via CCIP-Read such as *.cb.id) and Basenames (*.base.eth, read directly on Base) to a checksummed address; or, given an address, returns its primary ENS name and primary Basename, each forward-verified (the name must resolve back to the address). Names are normalized per ENSIP-15. Unresolvable names are not charged.

Use before sending a transaction or to tell a user what it will cost: reads eth_feeHistory over the last 20 blocks (10th/50th/90th percentile tips), the next base fee and gas price, on Base also the L1 data fee upper bound from the OP-stack GasPriceOracle, and prices typical actions (ETH transfer 21k gas, ERC-20 transfer 65k, DEX swap 180k) in ETH and USD (Chainlink ETH/USD).

Use when you have a token contract address and need to know what it is: reads name, symbol, decimals and totalSupply straight from the contract (one multicall) on Base or Ethereum, confirms there is contract code at the address, and adds a Chainlink USD price when one exists for the symbol. Answers 404 (not charged) when the address is not a token.