The Z3 Theorem Prover
C++ Python C# Java C OCaml Other
Latest commit c67cf16 Feb 15, 2017 @NikolajBjorner NikolajBjorner use non _ method from z3printer module so to be resilient against how…
… _ is handled as indicator of private functions

Signed-off-by: Nikolaj Bjorner <>


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.

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

Windows x86 Windows x64 Ubuntu x64 Ubuntu x86 Debian x64 OSX
win32-badge win64-badge ubuntu-x64-badge ubuntu-x86-badge debian-badge osx-badge

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

Building Z3 using make and GCC/Clang


python scripts/
cd build
sudo make install

Note by default gcc is used as the C++ compiler if it is available. If you would prefer to use Clang change the line 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 PREFIX/bin, libraries at PREFIX/lib, and include files at PREFIX/include, where PREFIX installation prefix if inferred by the script. It is usually /usr for most Linux distros, and /usr/local for FreeBSD and OSX. Use the --prefix= 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 an unofficial build system using CMake. Read the file for details.

Z3 bindings

Z3 has bindings for various programming languages.


Use the --dotnet command line flag with to enable building these.

On non-windows platforms mono is required. On these platforms the location of the C# compiler and gac utility need to be known. You can set these as follows if they aren't detected automatically. For example:

CSC=/usr/bin/csc GACUTIL=/usr/bin/gacutil python scripts/ --dotnet

Note for very old versions of Mono (e.g. 2.10) you may need to set CSC to /usr/bin/dmcs.

Note that when make install is executed on non-windows platforms the GAC utility is used to install Microsoft.Z3.dll into the GAC as the Microsoft.Z3.Sharp package. During install a pkg-config file (Microsoft.Z3.Sharp.pc) is also installed which allows the MonoDevelop IDE to find the bindings. Running make uninstall will remove the dll from the GAC and the pkg-config file.

See examples/dotnet for examples.


These are always enabled.

See examples/c for examples.


These are always enabled.

See examples/c++ for examples.


Use the --java command line flag with to enable building these.

See examples/java for examples.


Use the --ml command line flag with to enable building these.

See examples/ml for examples.


Use the --python command line flag with to enable building these.

Note that is required on certain platforms that the Python package directory (site-packages on most distributions and dist-packages on Debian based distributions) live under the install prefix. If you use a non standard prefix you can use the --pypkgdir 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.

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())'

See examples/python for examples.