Sunday, March 24, 2019

PyPy v7.1 released; now uses utf-8 internally for unicode strings

The PyPy team is proud to release version 7.1.0 of PyPy, which includes two different interpreters:
  • PyPy2.7, which is an interpreter supporting the syntax and the features of Python 2.7
  • PyPy3.6-beta: this is the second official release of PyPy to support 3.6 features, although it is still considered beta quality.
The interpreters are based on much the same codebase, thus the double release.

This release, coming fast on the heels of 7.0 in February, finally merges the internal refactoring of unicode representation as UTF-8. Removing the conversions from strings to unicode internally lead to a nice speed bump. We merged the utf-8 changes to the py3.5 branch (Python3.5.3) but will concentrate on 3.6 going forward.

We also improved the ability to use the buffer protocol with ctype structures and arrays.

The CFFI backend has been updated to version 1.12.2. We recommend using CFFI rather than c-extensions to interact with C, and cppyy for interacting with C++ code.
 You can download the v7.1 releases here:
We would like to thank our donors for the continued support of the PyPy project. If PyPy is not quite good enough for your needs, we are available for direct consulting work.

We would also like to thank our contributors and encourage new people to join the project. PyPy has many layers and we need help with all of them: PyPy and RPython documentation improvements, tweaking popular modules to run on pypy, or general help with making RPython’s JIT even better.

What is PyPy?

PyPy is a very compliant Python interpreter, almost a drop-in replacement for CPython 2.7, 3.6. It’s fast (PyPy and CPython 2.7.x performance comparison) due to its integrated tracing JIT compiler.

We also welcome developers of other dynamic languages to see what RPython can do for them.
This PyPy release supports:
  • x86 machines on most common operating systems (Linux 32/64 bits, Mac OS X 64 bits, Windows 32 bits, OpenBSD, FreeBSD)
  • big- and little-endian variants of PPC64 running Linux
  •  ARM32 although we do not supply downloadable binaries at this time
  • s390x running Linux

What else is new?

PyPy 7.0 was released in February, 2019. There are many incremental improvements to RPython and PyPy, for more information see the changelog.

Please update, and continue to help us make PyPy better.

Cheers, The PyPy team


  1. Hi,

    I get this error when trying to run my app with the new PyPy release (pypy 2.7 syntax on Windows):

    'C:\pypy2\lib_pypy\_sqlite3_cffi.pypy-41.pyd': The specified module could not be found

    The file specified in the error message (\lib_pypy\_sqlite3_cffi.pypy-41.pyd) is in the folder so whatever is missing is not quite so obvious.

  2. One question about using utf8 text encoding, internally.

    Is text handling code much different now, in PyPy, vs. cPython?

    If handling characters ( code points ) within the ASCII range
    is more like Python v.2.x, that would be very good news to
    at least one old fart who is having trouble even treating
    print as a function ...


  3. @Noah The answer is complicated because CPython changed its internals more than once. The current CPython 3.x stores unicode strings as an array of same-sized characters; if your string contains even one character over 0xffff then it's an array of 4 bytes for all the characters. Sometimes CPython *also* caches the UTF8 string, but doesn't use it much. The new PyPy is very different: it uses the UTF8 string *only*, and it works for both PyPy 2.7 or 3.x.

  4. @Anonymous It works for me. Please open a bug report on and give more details...

  5. Hi Armin,

    I can't log in to but the problem is very easy to replicate, you only need to test this and it fails (v6.0.0 works fine but both v7.0.0 and 7.1.0 fail):

    import sqlite3
    except Exception as e:
    print str(e)

    The error is:
    'C:\pypy27v710\lib_pypy\_sqlite3_cffi.pypy-41.pyd': The specified module could not be found

    I've tested it on two different Win10 PCs (32bit PyPy on 64bit Win10) and both exhibit the same behaviour.

    1. It is not so easy, because it works fine for me (win10 too). Please file a regular bug report. If you can't then we have another problem to solve first...

  6. Hi Armin,

    I've got the answer: With PyPy version >= 7.0.0 you have to add PyPy's root folder to PATH in Environment Variables, that wasn't required with versions <= 6.0.0


  8. Hi Armin,

    Moving the dlls to lib_pypy is a nice easy workaround, thank you.

    And thanks to everybody in the PyPy team for their excellent work.


See also PyPy's IRC channel: #pypy at, or the pypy-dev mailing list.
If the blog post is old, it is pointless to ask questions here about it---you're unlikely to get an answer.