specification: API Commons Rate Limits
specificationVersion: '0.1'
schema: https://raw.githubusercontent.com/api-evangelist/interface-research/main/schema/api-commons.yml#/$defs/RateLimits
provider: NASA
providerId: nasa
created: '2026-05-04'
# Provenance stamped 2026-08-11: this artifact was written by the API Evangelist
# bulk sweep dated 2026-05-04, not harvested from the provider. See roadmap#35.
method: generated
modified: '2026-05-05'
reconciled: true
tags:
  - Rate Limiting
  - Government
  - Science
  - Space
description: NASA Open APIs run on the api.data.gov shared gateway. Rate limits are scoped per-API-key
  for signed-up keys and per-IP for the shared DEMO_KEY. There are no separate live/sandbox modes; higher
  limits require contacting api@nasa.gov. Counters reset on a rolling hourly basis.
sources:
  - https://api.nasa.gov/
  - https://api.nasa.gov/assets/html/authentication.html
  - https://api.data.gov/docs/rate-limits/
headers:
  limit: X-RateLimit-Limit
  remaining: X-RateLimit-Remaining
responseCodes:
  throttled: 429
  quotaExceeded: 429
limits:
  - name: Signed-up API key (default)
    scope: key
    metric: requests_per_hour
    limit: 1000
    timeFrame: hour
    notes: Default for all signed-up keys across every NASA API at api.nasa.gov.
  - name: DEMO_KEY hourly
    scope: IP
    metric: requests_per_hour
    limit: 30
    timeFrame: hour
    notes: Shared demo key — limit is per IP address, not per key.
  - name: DEMO_KEY daily
    scope: IP
    metric: requests_per_day
    limit: 50
    timeFrame: day
    notes: Shared demo key daily ceiling per IP.
policies:
  - name: Rolling window
    description: The hourly window resets on a rolling basis rather than at a fixed clock minute. After
      a block, access resumes within an hour without intervention.
  - name: Demo key vs signed key
    description: DEMO_KEY is intended only for tutorials and exploration; production traffic should use
      a signed-up key. DEMO_KEY limits are enforced per IP and shared across all consumers from that IP.
  - name: Higher limits via email
    description: Consumers needing more than 1,000 requests/hour are directed to email api@nasa.gov to
      request an allowlist; some upstream APIs (e.g. Earthdata, NASA POWER) have their own rate-limit
      policies documented separately.
  - name: Backoff
    description: On 429, wait at least the remainder of the hour before resuming. There is no Retry-After
      header documented.
maintainers:
  - FN: Kin Lane
    email: kin@apievangelist.com