NYISO Metering API
NYISO's standalone Metering API, documented separately from the Finance APIs guide and served from its own root at api.nyiso.com/metering. It covers submission and retrieval of hourly revenue-grade meter data for generators, ties and subzones via POST and GET /v1/powerMetering, and retrieval of calculated subzone load via GET /v1/calculatedSubzoneLoad/summary and /v1/calculatedSubzoneLoad/detail. JSON bodies, ISO-8601 dates and times, HTTPS 1.1 over TLS 1.2, and a rolling three-year-and-ten-month data availability window ending with the current month. Two-factor authentication is required - MIS user account and password via HTTP Basic plus the NAESB certificate associated with that account on every request. The root and /v1/powerMetering both returned 401 Authorization Required to anonymous probes on 2026-07-27.