Since (at least) year 2016 when the moratorium was lifted there has been a max of 10 challenge checker runs per 24 hour period, for non Plus members of Project-GC. Plus members does not have a rate-limit.
The rate-limits has been approved by Geocaching HQ. We provide the challenge checker service for free, with such limitation. Or, one can pay the ~20 EUR yearly fee to remove that limitation (and get more features unlocked). In our defense, we have spent thousands of work hours on this system, creating it, hosting it, and maintaining it. Without Project-GC there most likely wouldn't have been any challenges the last 10 years, the moratorium probably wouldn't have been lifted.
There are a few exceptions to the rate-limits though. Besides that Reviewers and Plus members don't have rate-limits at all, it used to be that "Taggers" (a special permission group one has to apply for) didn't have any rate-limits at all (for running Challenge checkers). This is *not* the case anymore. You are a member of that group, so basically you have had this for free for ~10 years.
PS! There is also a ten day free trial that can be activated once per year to temporary bypass the rate-limits.
