The Swiftype crawler supports the rel="nofollow" standard.
<a href="/some/page" rel="nofollow">Do not follow this link</a>
Since Swiftype only follows links on the same domain, this is mostly useful for crawl prioritization. For example, you could put
rel="nofollow" on your sign in and create account links, and Swiftype will not waste time trying to follow them.