Building PyPy from Source

For building PyPy, we recommend installing a pre-built PyPy first (see Downloading and Installing PyPy). It is possible to build PyPy with CPython, but it will take a lot longer to run – depending on your architecture, between two and three times as long.

Even when using PyPy to build PyPy, translation is time-consuming – 30 minutes on a fast machine – and RAM-hungry. You will need at least 2 GB of memory on a 32-bit machine and 4GB on a 64-bit machine.

Clone the repository

If you prefer to compile your own PyPy, or if you want to modify it, you will need to obtain a copy of the sources. This can be done either by downloading them from the download page or by checking them out from the repository using mercurial. We suggest using mercurial if you want to access the current development.

You must issue the following command on your command line, DOS box, or terminal:

hg clone pypy

This will clone the repository and place it into a directory named pypy, and will get you the PyPy source in pypy/pypy and documentation files in pypy/pypy/doc. We try to ensure that the tip is always stable, but it might occasionally be broken. You may want to check out our nightly tests: find a revision (12-chars alphanumeric string, e.g. “963e808156b3”) that passed at least the {linux32} tests (corresponding to a + sign on the line success) and then, in your cloned repository, switch to this revision using:

hg up -r XXXXX

where XXXXX is the revision id.

Install build-time dependencies

(Note: for some hints on how to translate the Python interpreter under Windows, see the windows document . For hints on how to cross-compile in a chroot using scratchbox2, see the arm document in the RPython documentation)

The host Python needs to have CFFI installed. If translating on PyPy, CFFI is already installed. If translating on CPython, you need to install it, e.g. using pip install cffi.

To build PyPy on Unix using the C translation backend, you need at least a C compiler and make installed. Further, some optional modules have additional dependencies:

cffi, ctypes
libffi, pkg-config
libunwind (optional, loaded dynamically at runtime)

Make sure to have these libraries (with development headers) installed before building PyPy, otherwise the resulting binary will not contain these modules. Furthermore, the following libraries should be present after building PyPy, otherwise the corresponding CFFI modules are not built (you can run or re-run pypy/tool/release/ to retry to build them; you don’t need to re-translate the whole PyPy):

libncurses-dev (for PyPy2) libncursesw-dev (for PyPy3)
lzma (PyPy3 only)

To run untranslated tests, you need the Boehm garbage collector libgc.

On Debian and Ubuntu, this is the command to install all build-time dependencies:

apt-get install gcc make libffi-dev pkg-config libz-dev libbz2-dev \
libsqlite3-dev libncurses-dev libexpat1-dev libssl-dev libgdbm-dev \
tk-dev libgc-dev python-cffi \
liblzma-dev libncursesw-dev      # these two only needed on PyPy3

On Fedora:

dnf install gcc make libffi-devel pkgconfig zlib-devel bzip2-devel \
sqlite-devel ncurses-devel expat-devel openssl-devel tk-devel \
gdbm-devel python-cffi\
xz-devel  # For lzma on PyPy3.

On SLES11:

zypper install gcc make python-devel pkg-config \
zlib-devel libopenssl-devel libbz2-devel sqlite3-devel \
libexpat-devel libffi-devel python-curses python-cffi \
xz-devel # For lzma on PyPy3.
(XXX plus the SLES11 version of libgdbm-dev and tk-dev)

On Mac OS X, most of these build-time dependencies are installed alongside the Developer Tools. However, note that in order for the installation to find them you may need to run:

xcode-select --install

Run the translation

Translate with JIT:

cd pypy/goal
pypy ../../rpython/bin/rpython --opt=jit

Translate without JIT:

cd pypy/goal
pypy ../../rpython/bin/rpython --opt=2

(You can use python instead of pypy here, which will take longer but works too.)

If everything works correctly this will create an executable pypy-c in the current directory. The executable behaves mostly like a normal Python interpreter (see Differences between PyPy and CPython).

Build cffi import libraries for the stdlib

Various stdlib modules require a separate build step to create the cffi import libraries in the out-of-line API mode. This is done by the following command:

cd pypy/goal
PYTHONPATH=../.. ./pypy-c ../tool/

Translating with non-standard options

It is possible to have non-standard features enabled for translation, but they are not really tested any more. Look, for example, at the objspace proxies document.

Packaging (preparing for installation)

Packaging is required if you want to install PyPy system-wide, even to install on the same machine. The reason is that doing so prepares a number of extra features that cannot be done lazily on a root-installed PyPy, because the normal users don’t have write access. This concerns mostly libraries that would normally be compiled if and when they are imported the first time.

cd pypy/tool/release
./ --archive-name=pypy-VER-PLATFORM

This creates a clean and prepared hierarchy, as well as a .tar.bz2 with the same content; both are found by default in /tmp/usession-YOURNAME/build/. You can then either move the file hierarchy or unpack the .tar.bz2 at the correct place.

It is recommended to use because custom scripts will invariably become out-of-date. If you want to write custom scripts anyway, note an easy-to-miss point: some modules are written with CFFI, and require some compilation. If you install PyPy as root without pre-compiling them, normal users will get errors:

  • PyPy 2.5.1 or earlier: normal users would see permission errors. Installers need to run pypy -c "import gdbm" and other similar commands at install time; the exact list is in ``_. Users seeing a broken installation of PyPy can fix it after-the-fact if they have sudo rights, by running once e.g. sudo pypy -c "import gdbm.
  • PyPy 2.6 and later: anyone would get ImportError: no module named _gdbm_cffi. Installers need to run pypy in the lib_pypy directory during the installation process (plus others; see the exact list in ``_). Users seeing a broken installation of PyPy can fix it after-the-fact, by running pypy /path/to/lib_pypy/ This command produces a file called locally, which is a C extension module for PyPy. You can move it at any place where modules are normally found: e.g. in your project’s main directory, or in a directory that you add to the env var PYTHONPATH.


PyPy dynamically finds the location of its libraries depending on the location of the executable. The directory hierarchy of a typical PyPy installation looks like this:


The hierarchy shown above is relative to a PREFIX directory. PREFIX is computed by starting from the directory where the executable resides, and “walking up” the filesystem until we find a directory containing lib_pypy and lib-python/2.7.

To install PyPy system wide on unix-like systems, it is recommended to put the whole hierarchy alone (e.g. in /opt/pypy) and put a symlink to the pypy executable into /usr/bin or /usr/local/bin.

If the executable fails to find suitable libraries, it will report debug: WARNING: library path not found, using compiled-in sys.path and then attempt to continue normally. If the default path is usable, most code will be fine. However, the sys.prefix will be unset and some existing libraries assume that this is never the case.