Web Service Rate Limits¶
Limits are placed on the number of API requests you may make using your API key. Rate limits may vary by service, but the defaults are:
Hourly Limit: 1,000 requests per hour
For each API key, these limits are applied across all api.nasa.gov API requests. Exceeding these limits will lead to your API key being temporarily blocked from making further requests. The block will automatically be lifted by waiting an hour. If you need higher rate limits, contact us.
DEMO_KEY Rate Limits¶
In documentation examples, the special DEMO_KEY api key is used. This API key can be used for initially exploring APIs prior to signing up, but it has much lower rate limits, so you’re encouraged to signup for your own API key if you plan to use the API (signup is quick and easy).
The rate limits for the DEMO_KEY are:
Hourly Limit: 30 requests per IP address per hour
Daily Limit: 50 requests per IP address per day
How Do I See My Current Usage?
You can check your current rate limit and usage details by inspecting the X-RateLimit-Limit and X-RateLimit-Remaining HTTP headers that are returned on every API response. For example, if an API has the default hourly limit of 1,000 request, after making 2 requests, you will receive this HTTP header in the response of the second request:
* Your current limit remaining is stored in the limit_remaining instance variable.
Note
If you exceed your rate limit, you will be notified with an error message on your next request, so you do not have to check limit_remaining every time.
Although if you want to prevent your API key for being temporarily blocked here’s how you can access it:
1import pyspace
2
3nasa = pyspace.PySpace()
4print(f"Limit Remaining: {nasa.limit_remaining}")
The hourly counters for your API key reset on a rolling basis.
Example: If you made 500 requests at 10:15AM and 500 requests at 10:25AM, your API key would become temporarily blocked. This temporary block of your API key would cease at 11:15AM, at which point you could make 500 requests. At 11:25AM, you could then make another 500 requests.
Note
Anyone can register for an api.nasa.gov key, which can be used to access data across federal agencies.