SPP Portal Chart API
JSON and CSV chart feeds serving the SPP Portal dashboards. Confirmed anonymously on 2026-07-27: /chart-api/gen-mix/asChart and /chart-api/load-forecast/asChart return application/json with labelled hourly datasets by fuel type and load forecast series, and /chart-api/gen-mix-365/asFile returns a rolling 365-day generation mix CSV. Undocumented as a formal interface specification; served without authentication.