Z3

Z3 is ranked #2 of 33 in formal verification tools on Freedom251. It runs on Android, API, Linux, macOS, Self-hosted, Web, Windows. There is a free plan.

Z3 plans and pricing

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Z3 (MIT licensed) Free MIT-licensed downloads and source code github.com · 2 Oct 2026

Compared on formal verification tools

Free plan: Yes
Supported formalisms: theorem-proving
Counterexamples: Yes
Proof artifacts: Yes
Input languages: SMT-LIB2, C, C++, .NET, Java, Python, Rust, OCaml, Julia, JavaScript, TypeScript, Smalltalk, Go
Deployment: self-hosted

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Purpose: Z3 is a theorem prover and satisfiability modulo theories (SMT) solver.
SMT-LIB: Z3 supports the SMTLIB format.
Applications: Z3 is used in software verification and analysis applications.
Input: SMTLIB2 is Z3’s default input format.
Build systems: Z3 can be built using CMake, vcpkg, or Bazel.
Language interfaces: The repository documents bindings or APIs for C, C++, .NET, Java, Go, OCaml, Python, Julia, and JavaScript/TypeScript.
Browser use: The project wiki links to a page for trying Z3 in a browser.
Platforms: The project wiki lists Windows, OSX, Linux (Ubuntu and Debian), and FreeBSD as supported platforms.
Downloads: The repository links to pre-built binaries for stable and nightly releases.
License: The repository states that Z3 is licensed under the MIT license.
Security: The README says MSVC builds enable Control Flow Guard and Address Space Layout Randomization by default.
Dependencies: Python is required to build Z3, and additional toolchains are needed to build Java, .NET, OCaml, and Julia APIs.
Support: The project wiki says to contact the creator of an external binding package for support issues.
Price from: Free

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Where it ranks on Freedom251

Best Formal Verification Tools in 2026#2 of 33

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Sources

github.com/Z3Prover/z3· checked 2 Oct 2026
github.com/Z3Prover/z3/wiki· checked 2 Oct 2026
microsoft.com/en-us/research/publication/z3-an-effici· checked 2 Oct 2026