This paper discusses several formal verification instruments and compares them. These tools are Isabelle/HOL, Coq, Verdi, and TLA+. All of them are developed for automatic verification of distributed systems. However, there are a number of differences in implementation and application. Verdi provides an effortless way of implementation to verify some distributed systems. Isabelle/HOL and Coq, on the other hand, can solve a wider range of tasks. These provide a low-level interface and require programming skills. TLA+ allows the user to communicate in pseudocode-like language as well as per algorithm implementation in TLA+/PlusCal. It is the most versatile tool for formal verification which is considered in this paper.