National Renewable Energy Laboratory · Rate Limits

National Renewable Energy Laboratory Rate Limits

NREL APIs are fronted by the api.data.gov gateway and apply per-API-key rate limits for signed-up keys and per-IP limits for the shared DEMO_KEY. Per-service variation is possible (some APIs publish their own quotas), but the platform default is 1,000 requests per hour. Counters reset on a rolling hourly basis; 429 is the throttling response.

3 Limits Throttle: 429 Quota: 429
Rate LimitingGovernmentEnergyRenewables

Limits

Signed-up API key (default) key
requests_per_hour · hour
1000
Default for all signed-up keys across every NREL API; some services may publish their own caps.
DEMO_KEY hourly IP
requests_per_hour · hour
30
Shared demo key — limit is per IP address, not per key.
DEMO_KEY daily IP
requests_per_day · day
50
Shared demo key daily ceiling per IP.

Policies

Rolling window
Hourly limits reset on a rolling basis. After a 429 block, the key automatically resumes service within an hour.
Demo vs signed key
DEMO_KEY is for documentation / tutorial use only; production traffic should use a free signed-up API key.
Service-specific overrides
Some NREL APIs document their own per-service quotas; consult the individual API documentation page when those are stricter than the gateway default.
Domain migration
developer.nrel.gov is being retired in May 2026. Consumers should migrate to developer.nlr.gov to avoid disruption.

Sources