Associate Professor in Introduction to Law and State, Law and Justice, and Philosophy of Law at the Faculty of Law of University of Belgrade (Serbia) and a Visiting Professor at Bocconi University (Milan, Italy). He was an Alexander von Humboldt Research Fellow at the University of Heidelberg (Germany), Erasmus+ Teaching Exchange Fellow at the University of Bologna (Italy) and Italian Government Research Fellow at the University La Sapienza in Rome (Italy).
Spai? is the head of the Center for Legal Fundamentals of the Institute for Legal and Social Sciences of the Faculty of Law of University of Belgrade. President of the Serbian section of the International Association for the Philosophy of Law and Social Philosophy. Head of Belgrade Legal Theory Group, and coordinates the Horizon Twinning project Advancing Cooperation on the Foundations of Law (ALF). He has published (as an editor and author) 11 books and more than 30 articles in Serbian and English.