EIA Open Data API v2

API v2 is how machines read EIA's catalog. Its documentation — 'EIA API Technical Documentation (v2 Routes & Facets)' — enumerates the feature set: route-tree metadata discovery, api_key authentication, facet and frequency filters, pagination, sorting, facet-value lookup, and v1 series-ID translation for legacy identifiers.

Access and abuse handling are documented too. 'integration keys are free and issued by email upon registration.' On the limits side, 'routes exceeding 2M+ series are throttled per second/hour', with enforcement that escalates only temporarily: 'temporary automatic key suspension with automatic reactivation after a cooldown.' The design intent is a self-service API that stays responsive by shaping demand rather than banishing users.

Bulk pulls die on undocumented limits. Knowing that 2M+-series routes are throttled per second/hour before you write the downloader is the difference between a scheduled job and a suspended key discovered at 3 a.m.

Feature coverage matters just as much. Route-tree discovery means clients can enumerate what exists without a separate data dictionary; frequency filters and pagination mean one interface handles both a single series and a full sweep; v1 series-ID translation protects investments made against the previous API generation. A source lacking these forces custom glue code that becomes your maintenance burden.

1. Start at the route tree. Metadata discovery should reveal the hierarchy before any data call.
2. Exercise facets and frequencies. Filtered, frequency-scoped queries are the documented pattern.
3. Budget against the throttle. Plan for per-second/per-hour caps on routes exceeding 2M+ series.
4. Expect suspension, not exile. Enforcement is 'temporary automatic key suspension with automatic reactivation after a cooldown' — design retry logic accordingly.
5. Reuse v1 translations. Map legacy series IDs instead of rebuilding them.

Power-sector context: balancing-authority, form-eia-860, pjm-data-miner-2, and independent-power-producers-energy-traders data.

• balancing-authority — the grid geography behind many v2 routes.
• form-eia-860 — a generator-level collection reachable through the API.
• pjm-data-miner-2 — an ISO-side alternative interface for market participants.