Well, there's no governing body of fire spinning, so there isn't really a license. Most performance venues and troops do require that all fire spinners carry insurance (most commonly this is from Performers of the US: www.specialtyinsuranceagency.com/ ). But Insurance is only one piece of the equation. Because anybody with enough money can purchase the insurance regardless of their competence (and many very talented spinners can't afford it) the community tends to supplement the insurance requirement with an informal reputation based system.

This is a significant problem for the community because without a more rigid skill & safety certification it can put people on stage with fire who really aren't ready, and that is dangerous for everyone. And, if one performance goes wrong in a city it can really put an end to fire gigs. Dance Afire is working on developing a better system for representing the level of training/experience a performer has, but its difficult because of (a) the subjective nature of skill, (b) the traditional ad hoc skill sharing model, and (c) potential liability concerns for the certifying entity (i.e., if someone is a Dance Afire certified performer and they burn down a building, are we liable? we better not be!)