All API calls are limited to 30 requests every 10 seconds. Once this limit has been reached, calls will return and error with status code 429. This rate limit is evaluated on a rolling window basis. API requests are limited to the amount specified in the returned X-RateLimit-Limit header (per 10 seconds). Exceeding that limit will cause BSPK to return an HTTP 429 response. Check the X-RateLimit-Limit and X-RateLimit-Remaining headers to see how many more requests you are allowed until throttling kicks in. 
$ curl -I --header "Authorization: Bearer TOKEN" \
https://api.bspk.com/api/extraction/v1/appointments

> HTTP/1.1 200 OK
> Date: Sat, 07 Aug 2021 00:17:40 GMT
> Content-Type: application/json; charset=utf-8
> X-Ratelimit-Limit: 30
> X-Ratelimit-Remaining: 29
Whenever the rate limit is reached, in addition to the other headers you will also receive the X-RateLimit-Reset which you can use to smartly call our API again only after rate limit window is reseted.
keyeg. valueDescription
RateLimit-Reset1628304730The remaining window before the rate limit resets in UTC epoch seconds
You can use your desired programing language to convert the UTC epoch seconds to DateTime so that you can use it.