Register for an ISO Express account at iso-ne.com; publicly available operational data is automatically granted, while some participant-specific data requires additional authorization.
Review the API documentation at https://webservices.iso-ne.com/docs/v1.1/ and the WADL descriptor at https://webservices.iso-ne.com/api/v1.1?_wadl to enumerate available resource endpoints.
Issue HTTP GET requests to the REST base URL https://webservices.iso-ne.com/api/v1.1/{resource} appending .json or .xml for format selection, or set the Accept header to application/json or application/xml.
Pass HTTP Basic Authentication credentials (ISO Express username and password) on each request; the API does not use a separate API key — credentials are the same as the web portal login.
Query key resources such as /hourlylmps/day/{date} for hourly LMPs, /genfuelmix/day/{date} for generation fuel mix, /sysload/day/{date} for system load, and /nepool/prices for day-ahead prices.
Handle pagination: some resource responses include a 'moreDataAvailable' flag; use the provided nextLink to retrieve subsequent pages.
Known gotchas
The API uses a v1.1 path that has been stable but ISO-NE periodically adds resources; check the WADL or the business documentation spreadsheet (downloadable from iso-ne.com) for newly added feeds before building workarounds.
ISO-NE timestamps are in Eastern Prevailing Time with hour-ending convention; the fall-back DST hour produces a repeated hour in daily files — always store with explicit UTC offsets.
Some reports (e.g., final settlement LMPs) are only available after a multi-day finalization period; real-time and preliminary data endpoints exist separately from final-settlement endpoints and will return different values for the same interval.
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp