Different types of rate limits are defined in different parts of the Reblaze interface.
Global: The Static Rules -> Speed & Rate settings apply to your entire planet.
By location: Rate limits for specific locations/URLs can be created by defining the locations within Web Proxy -> Security Profiles, and selecting "More" at the end of each location's entry in the list. See full explanation here: Setting Rate Limits for a Location.
By traffic source: Requestors who are submitting excessive requests can be banned for configured lengths of time. This can be done via Dynamic Rules.
Creating exemptions from rate limits is done differently, depending on the scope of the rate limits being addressed.
Global: Create an ACL Policy with an OC suffix.
By location: Create an ACL Policy with the name "Rate Limit Whitelist". This can exempt any combination of IP, Country, and ASN. The Policy should then be included in a Profile, and the Profile should be assigned to the appropriate location(s) or portions of your site/application. Example:
By traffic source: A traffic source can be exempted from Dynamic Rule filtering either by adding an Ignore parameter to the Rule itself, or by adding the traffic source to the Whitelist within the Quarantine section.