The article is devoted to the problems of determining the methodological bases for the development of the country’s tax policy. The institutional powers of the main regulators of tax policy are defined. These regulators, when interacting, must comply with the criteria of Nash equilibrium in order to ensure sustainable socioeconomic development. The principles of formation and implementation of tax policy are characterized, in particular, fiscal sufficiency, social justice, efficiency, effectiveness, stability, adaptability and neutrality in relation to the level of competitiveness of the payer. A two-stage algorithm for determining the efficiency and effectiveness of tax policy has been proposed. The specifics of planning and forecasting activities in the system of tax regulation of socioeconomic development are disclosed, the need for permanent improvement of the methodology of medium-term planning of tax revenues and introduction of scenario modeling is substantiated. The need to assess the financial solvency of taxpayers in order to build realistic forecasts and plans is emphasized. The reasons for the occurrence of transaction costs associated with the administration of taxes are disclosed, a methodical approach to their distribution into ex ante and ex post expenses is substantiated. The features of the formation of tax policy under the conditions of further implementation of the reform of fiscal decentralization and taking into account Samuelson’s «randomness theorem» are determined. The need to find optimal parameters for the distribution of revenues from the payment of national taxes between the State and local budgets is emphasized. The role of the information component in the environment of development and implementation of tax policy is defined. The basic characteristics of the architecture of effective tax administration are determined. Promising directions of digitalization of tax administration have been identified, taking into account the peculiarities of the architectonics of fiscal space.