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The Z3 Theorem Prover

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Z3 is a theorem prover from Microsoft Research. It is licensed under the MIT license.

If you are not familiar with Z3, you can start here.

Pre-built binaries for stable and nightly releases are available from here.

Z3 can be built using Visual Studio, a Makefile or using CMake. It provides bindings for several programming languages.

See the release notes for notes on various stable releases of Z3.

Build status

| Azure Pipelines | Code Coverage | Open Bugs | Android Build | | --------------- | --------------|-----------|---------------| | Build Status | CodeCoverage | Open Issues |Android Build |

Building Z3 on Windows using Visual Studio Command Prompt

32-bit builds, start with:

python scripts/

or instead, for a 64-bit build:

python scripts/ -x


cd build

Z3 uses C++17. The recommended version of Visual Studio is therefore VS2019.

Building Z3 using make and GCC/Clang


python scripts/
cd build
sudo make install

Note by default

is used as the C++ compiler if it is available. If you would prefer to use Clang change the
invocation to:
CXX=clang++ CC=clang python scripts/

Note that Clang < 3.7 does not support OpenMP.

You can also build Z3 for Windows using Cygwin and the Mingw-w64 cross-compiler. To configure that case correctly, make sure to use Cygwin's own python and not some Windows installation of Python.

For a 64 bit build (from Cygwin64), configure Z3's sources with

CXX=x86_64-w64-mingw32-g++ CC=x86_64-w64-mingw32-gcc AR=x86_64-w64-mingw32-ar python scripts/
A 32 bit build should work similarly (but is untested); the same is true for 32/64 bit builds from within Cygwin32.

By default, it will install z3 executable at

, libraries at
, and include files at
, where
installation prefix if inferred by the
script. It is usually
for most Linux distros, and
for FreeBSD and macOS. Use the
command line option to change the install prefix. For example:
python scripts/ --prefix=/home/leo
cd build
make install

To uninstall Z3, use

sudo make uninstall

To clean Z3 you can delete the build directory and run the
script again.

Building Z3 using CMake

Z3 has a build system using CMake. Read the file for details. It is recommended for most build tasks, except for building OCaml bindings.


Z3 itself has few dependencies. It uses C++ runtime libraries, including pthreads for multi-threading. It is optionally possible to use GMP for multi-precision integers, but Z3 contains its own self-contained multi-precision functionality. Python is required to build Z3. To build Java, .Net, OCaml, Julia APIs requires installing relevant tool chains.

Z3 bindings

Z3 has bindings for various programming languages.


You can install a nuget package for the latest release Z3 from

Use the

command line flag with
to enable building these.


for examples.


These are always enabled.


for examples.


These are always enabled.


for examples.


Use the

command line flag with
to enable building these.


for examples.


Use the

command line flag with
to enable building these.


for examples.


You can install the Python wrapper for Z3 for the latest release from pypi using the command

   pip install z3-solver

Use the

command line flag with
to enable building these.

Note that is required on certain platforms that the Python package directory (

on most distributions and
on Debian based distributions) live under the install prefix. If you use a non standard prefix you can use the
option to change the Python package directory used for installation. For example:
python scripts/ --prefix=/home/leo --python --pypkgdir=/home/leo/lib/python-2.7/site-packages

If you do need to install to a non standard prefix a better approach is to use a Python virtual environment and install Z3 there. Python packages also work for Python3. Under Windows, recall to build inside the Visual C++ native command build environment. Note that the

directory should be accessible from where python is used with Z3 and it depends on
to be in the path.
virtualenv venv
source venv/bin/activate
python scripts/ --python
cd build
make install
# You will find Z3 and the Python bindings installed in the virtual environment
venv/bin/z3 -h
python -c 'import z3; print(z3.get_version_string())'


for examples.


The Julia package Z3.jl wraps the C++ API of Z3. Information about updating and building the Julia bindings can be found in src/api/julia.

Web Assembly

WebAssembly bindings are provided by Clément Pit-Claudel.

System Overview

System Diagram


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