In our website, we see many crawlers which pretends like human trying get contents. These crawlers are not well known like Google/Bing/Facebook etc. I can identify those crawler's IP and they are using user agent as normal browser agent. In order to restrict access, we are thinking to add rate limit, for example if 10 calls are made then 4 time we could deny and allow 6 times. The reason we are thinking to do this is because each request cost money to customer because of the Content management system software pricing model. More content requests means more money needs to be paid.

So, the question is, if we add rate limit then will it have bad impact on SEO?