Static verification of a program source code correctness is an important element of software reliability. Formal verification of software programs involves proving that a program satisfies a formal specification of its behavior. Many languages use both static and dynamic type checking. With such approach, the static type checker verifies everything possible at compile time, and the dynamic one checks the remaining. The current state of the Jolie programming language includes a dynamic type

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... m. Consequently, it allows avoidable run-time errors. A static type system for the language has been formally defined on paper but lacks an implementation yet. In this paper, we describe a prototype of Jolie Static Type Checker (JSTC), which employs a technique based on a SMT solver. We describe the theory behind and the implementation, and the process of static analysis. The article is published in the authors' wording.