Software, APIs and data
Northline ChainKit: pay-per-call onchain checks for agents (address preflight, payment verify, tx explain)
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x402 API for AI agents on Base and Arc: preflight an address before paying it (EOA vs contract, proxy, Safe, Sourcify verification, risk flags), verify that a USDC payment really landed, explain a transaction as plain JSON, network fees, USDC balances. $0.001 to $0.005 per call in USDC on Base, no API key, no signup.