Z3 is an efficient SMT solver developed by Microsoft Research. It is used in various software verification and analysis applications. SMT extends SAT by adding reasoning about theories such as arithmetic, bit-vectors, arrays, and uninterpreted functions. Z3 integrates support for a variety of theories and uses novel algorithms for quantifier instantiation and theory combination. It was first released in September 2007 and has been used in projects such as Spec#/Boogie, Pex, HAVOC, Vigilante, VCC, and Yogi. Z3 is implemented in C++ and includes a modern DPLL-based SAT solver, a core theory solver for equalities and uninterpreted functions, satellite solvers for arithmetic, arrays, etc., and an E-matching abstract machine for quantifiers. Z3 processes input formulas with an efficient simplifier, converts them into a data structure, and uses congruence closure and theory solvers to determine satisfiability. It also generates models and supports various input formats, including SMT-LIB, Simplify, and a low-level native format. Z3's performance is enhanced by techniques such as relevancy propagation, E-matching for quantifier instantiation, and efficient clause management. It is used in extended static checking, test case generation, and predicate abstraction. Z3 has been integrated with other projects, including SLAM/SDV. The paper describes Z3's architecture, clients, and theory combination methods, and references several related works.Z3 is an efficient SMT solver developed by Microsoft Research. It is used in various software verification and analysis applications. SMT extends SAT by adding reasoning about theories such as arithmetic, bit-vectors, arrays, and uninterpreted functions. Z3 integrates support for a variety of theories and uses novel algorithms for quantifier instantiation and theory combination. It was first released in September 2007 and has been used in projects such as Spec#/Boogie, Pex, HAVOC, Vigilante, VCC, and Yogi. Z3 is implemented in C++ and includes a modern DPLL-based SAT solver, a core theory solver for equalities and uninterpreted functions, satellite solvers for arithmetic, arrays, etc., and an E-matching abstract machine for quantifiers. Z3 processes input formulas with an efficient simplifier, converts them into a data structure, and uses congruence closure and theory solvers to determine satisfiability. It also generates models and supports various input formats, including SMT-LIB, Simplify, and a low-level native format. Z3's performance is enhanced by techniques such as relevancy propagation, E-matching for quantifier instantiation, and efficient clause management. It is used in extended static checking, test case generation, and predicate abstraction. Z3 has been integrated with other projects, including SLAM/SDV. The paper describes Z3's architecture, clients, and theory combination methods, and references several related works.