<p>PyPy is a <aclass="reference external"href="http://speed.pypy.org/">fast</a>, <aclass="reference external"href="compat.html">compliant</a> alternative implementation of the <aclass="reference external"href="http://python.org/">Python</a>
language (2.7.8 and 3.2.5). It has several advantages and distinct features:</p>
<blockquote>
<ulclass="simple">
<li><strong>Speed:</strong> thanks to its Just-in-Time compiler, Python programs
often run <aclass="reference external"href="http://speed.pypy.org/">faster</a> on PyPy. <aclass="reference external"href="http://en.wikipedia.org/wiki/Just-in-time_compilation">(What is a JIT compiler?)</a></li>
<li><strong>Memory usage:</strong> memory-hungry Python programs (several hundreds of
MBs or more) might end up taking <aclass="reference external"href="http://morepypy.blogspot.com/2009/10/gc-improvements.html">less space</a> than they do in CPython.</li>
<li><strong>Compatibility:</strong> PyPy is <aclass="reference external"href="compat.html">highly compatible</a> with existing python code.
<ul>
<li><pclass="first"><strong>Speed:</strong> thanks to its Just-in-Time compiler, Python programs
often run <aclass="reference external"href="http://speed.pypy.org/">faster</a> on PyPy. <aclass="reference external"href="http://en.wikipedia.org/wiki/Just-in-time_compilation">(What is a JIT compiler?)</a></p>
<p>“If you want your code to run faster, you should probably just use PyPy”
— Guido van Rossum (creator of Python)</p>
</li>
<li><pclass="first"><strong>Memory usage:</strong> memory-hungry Python programs (several hundreds of
MBs or more) might end up taking <aclass="reference external"href="http://morepypy.blogspot.com/2009/10/gc-improvements.html">less space</a> than they do in CPython.</p>
</li>
<li><pclass="first"><strong>Compatibility:</strong> PyPy is <aclass="reference external"href="compat.html">highly compatible</a> with existing python code.
It supports <aclass="reference external"href="https://cffi.readthedocs.org">cffi</a> and can run popular python libraries like <aclass="reference external"href="https://twistedmatrix.com/">twisted</a>
...
...
@@ -81,10 +85,14 @@
It supports <aclass="reference external"href="https://cffi.readthedocs.org">cffi</a> and can run popular python libraries like <aclass="reference external"href="https://twistedmatrix.com/">twisted</a>
and <aclass="reference external"href="https://www.djangoproject.com/">django</a>.</li>
<li><strong>Sandboxing:</strong> PyPy provides the ability to <aclass="reference external"href="features.html#sandboxing">run untrusted code</a> in a
fully secure way.</li>
<li><strong>Stackless:</strong> PyPy comes by default with support for <aclass="reference external"href="features.html#stackless">stackless mode</a>,
providing micro-threads for massive concurrency.</li>
<li>As well as other <aclass="reference external"href="features.html">features</a>.</li>
and <aclass="reference external"href="https://www.djangoproject.com/">django</a>.</p>
</li>
<li><pclass="first"><strong>Sandboxing:</strong> PyPy provides the ability to <aclass="reference external"href="features.html#sandboxing">run untrusted code</a> in a
fully secure way.</p>
</li>
<li><pclass="first"><strong>Stackless:</strong> PyPy comes by default with support for <aclass="reference external"href="features.html#stackless">stackless mode</a>,
providing micro-threads for massive concurrency.</p>
</li>
<li><pclass="first">As well as other <aclass="reference external"href="features.html">features</a>.</p>
</li>
</ul>
</blockquote>
<pclass="download"><aclass="reference external"href="download.html">Download and try out PyPy</a></p>