{"service":"sendcheck","what":"Pre-send verification for EVM addresses: EIP-55 checksum, wallet-vs-contract, outgoing activity, native/USDC/USDT balances, wrong-network and token-mismatch detection — the same engine as https://sendcheck.surge.sh","home":"https://sendcheck.surge.sh","payment":"x402 (HTTP 402) — USDC on Base, no account, no API key. Any x402 client pays and retries: https://docs.x402.org","discovery":"/.well-known/x402 (machine-readable x402 discovery document)","endpoints":[{"method":"GET","path":"/","cost":"free","description":"This service card."},{"method":"GET","path":"/validate?address=0x…","cost":"free","description":"Checksum-only pre-check (no chain data). Use before paying, so you never pay for a malformed address."},{"method":"POST","path":"/check","cost":"$0.01","body":{"address":"0x…","chain":"base"},"description":"Full check on one chain. chain: base | ethereum | arbitrum | optimism | polygon (default base)."},{"method":"POST","path":"/deep","cost":"$0.05","body":{"address":"0x…","chain":"base"},"description":"Deep scan: the same check across ALL five chains + wrong-network detection."}],"chains":[{"id":"base","name":"Base"},{"id":"ethereum","name":"Ethereum"},{"id":"arbitrum","name":"Arbitrum One"},{"id":"optimism","name":"Optimism"},{"id":"polygon","name":"Polygon"}],"verdictLevels":{"ok":"no red flags found","caution":"something incomplete or unusual — read verdict.reasons","warn":"strong signal something is off (e.g. active on a different network than expected)","danger":"do not send — burn address or checksum mismatch"},"responseShape":{"address":"normalized EIP-55","checksum":"{status,message}","chain":"per-chain facts","others":"other chains (deep only)","verdict":"{level,headline,next,gas,tokenMismatch,reasons}","report":"copyable text report","meta":"service/version/timing"}}