This question has been asked in the #api-developers channel of the Bittrex Slack Group a few times.
Here’s the important fragment of the discussion with somewhat an answer to our question.
July 2nd, 2017
Some user: seriously guys.. the rate limit.. what is it.. bittrex-bill: It varies by API call. If you hit the limit, you are abusing it. If you hit the limit a lot, you risk getting banned :] I dont have a clearer answer for you right now Some user: Is greater than 1 minute consistently 24/7 within an acceptable use? bittrex-bill: yes
That’s it! I personally wish they would update the API docs with a clear and hard limitation, but for now, when we’re writing code that is long-running, and executes in a loop, we should try to cap the requests around 1 request per minute per API method.