Dynamics CRM API Access Limits?

Hi CRM Team,

I am working on MS Dynamics CRM 2016 Online and On-Premise integration.

a) Is there any limits to access these MS dynamics CRM APIs on per day per user basis?

b) If there are limits, is it same for Online and On-Premise?

For example- If I am using one API say POST SalesOrder, how many times can I hit this same API in a DAY?

Regards,

Rajinder Singh