x402 Base Tools

Current Base gas: base fee, priority fee percentiles over the last 10 blocks, the L1 data fee of a typical transaction, and what an ETH transfer, an ERC-20 transfer, a USDC transferWithAuthorization (an x402 payment), a swap and an NFT mint cost now in ETH and USD (ETH/USD from Chainlink).

Profile of a Base address: wallet (EOA), EIP-7702 delegated wallet or contract; transaction count; ETH and USDC balances; its primary Basename; the token it is, if it is an ERC-20; and the x402 seller it receives payments for, from Bazaar listings.

Name, symbol, decimals and total supply of an ERC-20 token on Base, by address or well-known symbol, with its Basescan link.

The USD price of any ERC-20 on Base, read from its Uniswap v3 and Aerodrome pools against USDC and WETH (ETH/USD from Chainlink). The deepest pool sets the price; each pool's price and depth is listed, and thin markets are flagged. Accepts an address or a symbol such as ETH, USDC, cbBTC, AERO, DEGEN, VIRTUAL.

The ETH balance and ERC-20 balances of an address on Base, for the tokens you name or a default list of well-known tokens (USDC, WETH, cbBTC, AERO, DAI, USDT, DEGEN, VIRTUAL and others), with USD values for ETH, stablecoins and up to five other held tokens priced from their pools.

Everything about a Base transaction in one call: status, time, from and to, ETH value, the function called (for common selectors), the fee split into L2 execution and L1 data in ETH and USD, every ERC-20 transfer with symbol and readable amount, NFT transfers, and x402 payments (USDC transferWithAuthorization) with the seller named from Bazaar.

Check whether a Base transaction settled x402 payments (USDC transferWithAuthorization, EIP-3009): for each, the payer, the payTo address, the amount in USDC, the authorization nonce, the facilitator that sent it, and the seller behind the payTo address from Bazaar listings (origins and 30-day payers).

Resolve a Basename (name.base.eth) to its address, or find the primary Basename of an address (only when the name points back to it).

Whether a USDC transferWithAuthorization nonce of an authorizer has already been used on Base, which is how an x402 buyer tells a settled payment from one that never landed, plus the authorizer's USDC balance.