Abstract: Legal experiments in the field of taxation over the past 10 years have been an unconventional way of legislating various economic problems: for example, the task of removing the self-employed from the shadow economy was solved as part of a tax experiment to establish a tax on professional income. However, at present, legal experiments in tax law are applied not only at the legislative, but also at the subordinate level. The subject of this article is a set of procedural tax and organizational norms at the level of by-laws aimed at regulating tax relations. The purpose of this article is to substantiate and define the type of legal experiments at the level of subordinate legislation in the tax sphere. This goal will make it possible to take the first scientific steps in substantiating legal experiments in the tax sphere at the subordinate level. General scientific methods (generalization, comparative analysis, synthesis, description, system method), as well as special legal methods (formal legal method, method of interpretation of normative legal acts) are used. The result of the work on this study is the justification of the tax experiment and tax testing as an opportunity to conduct legal experiments at the level of by-laws. The scientific novelty is determined by the purpose of this article and consists in substantiating at the subordinate level the possibility of using a general theoretical model of a legal experiment as a tax test. The results obtained can become the basis for the preparation of educational literature on financial and tax law in the framework of pedagogical practice, and are also intended for use in the work of public authorities, as well as practicing lawyers and the scientific community. The key conclusion of this article is that tax testing is a legal experiment in the tax field, implemented at the subordinate level, which has its own specific features, such as the improvement of existing digital technologies, uncertainty about further permanent action, introduced by order of the federal executive authority authorized for control and supervision in the field of taxes and fees.

Keywords: legal experiment, tax experiment, tax testing, federal tax service, bylaws, tax legal relations, digital technologies, operators of electronic platforms, information interaction, tax administration