{"openapi":"3.1.0","info":{"title":"USGS Water Data","version":"1.0.0","description":"Real-time streamflow, gage height, and water-quality readings from thousands of USGS monitoring sites across the US. Machine-payable per request.","contact":{"email":"contact@meshgateway.co"},"x-guidance":"Every path is payable per request over HTTP 402 in USDG on eip155:4663. GET or POST without credentials to receive the challenge (WWW-Authenticate Payment header, plus the x402 payment-required header). Sign PermitWitnessTransferFrom for the advertised offer (spender is the canonical x402ExactPermit2Proxy) and retry with the payment-signature header. Buyers only need USDG: a one-time sponsored Permit2 approval is available at POST /api/gas/sponsor {\"address\"}."},"x-service-info":{"description":"Real-time streamflow, gage height, and water-quality readings from thousands of USGS monitoring sites across the US. Machine-payable per request."},"paths":{"/daily":{"get":{"summary":"Daily statistics per site. Pass ?format=json&sites=01646500&parameterCd=00060&startDT=2026-01-01&endDT=2026-01-31.","responses":{"200":{"description":"Successful response"},"402":{"description":"Payment Required"}},"x-payment-info":{"price":{"mode":"fixed","currency":"USD","amount":"0.005000"},"protocols":[{"mpp":{"method":"evm","intent":"charge","currency":"0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168"}},{"x402":{}}],"amount":"5000","currency":"0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168","description":"USGS Water Data: Daily values","intent":"charge","method":"evm","recipient":"0xbB818E97E2260904B1D502E154488392ba2Ab5C9","scheme":"exact","network":"eip155:4663","extra":{"assetTransferMethod":"permit2","spender":"0x402085c248EeA27D92E8b30b2C58ed07f9E20001","name":"USDG"}}}},"/instant":{"get":{"summary":"Latest sensor readings. Pass ?format=json&sites=01646500&parameterCd=00060,00065 (00060 = discharge cfs, 00065 = gage height ft); add &period=P1D for a day of history.","responses":{"200":{"description":"Successful response"},"402":{"description":"Payment Required"}},"x-payment-info":{"price":{"mode":"fixed","currency":"USD","amount":"0.005000"},"protocols":[{"mpp":{"method":"evm","intent":"charge","currency":"0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168"}},{"x402":{}}],"amount":"5000","currency":"0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168","description":"USGS Water Data: Instantaneous values","intent":"charge","method":"evm","recipient":"0xbB818E97E2260904B1D502E154488392ba2Ab5C9","scheme":"exact","network":"eip155:4663","extra":{"assetTransferMethod":"permit2","spender":"0x402085c248EeA27D92E8b30b2C58ed07f9E20001","name":"USDG"}}}}}}