Cython: C-Extensions for Python

Cython is an optimising static compiler for both the Python programming language and the extended Cython programming language (based on Pyrex). It makes writing C extensions for Python as easy as Python itself.
Cython gives you the combined power of Python and C to let you
The Cython language is a superset of the Python language that additionally supports calling C/C++ functions and declaring C/C++ types on variables and class attributes. This allows the compiler to generate very efficient C code from Cython code. The C code is generated once and then compiles with all major C/C++ compilers in CPython 3.8 and all later versions. Cython 3.0.x supports Python 2.7 / 3.5 and later. We regularly run integration tests against all supported CPython versions and their latest in-development branches to make sure that the generated code stays widely compatible and well adapted to each version. PyPy support is mostly usable. The latest PyPy version is always recommended here. Support for the CPython Limited API and free-threading CPython is available in Cython 3.1 but considered experimental.
All of this makes Cython the ideal language for wrapping external C libraries, embedding CPython into existing applications, and for fast C modules that speed up the execution of Python code.
Making Cython a great programming language for you, and keeping it up to speed with the Python ecosystem and the changing requirements of its diverse user bases, takes a lot of time and dedication. To support the maintenance and future development of the Cython language and compiler, YOU can sponsor the work of Stefan Behnel via:
Note that PayPal takes 5 - 15% fees for small non-EUR payments, which is money that you pay without helping us. Consider signing up for a GitHub Sponsors subscription instead.
If you still have questions, feel free to send an email to the cython users mailing list. Aspects of the core development are discussed on the cython core developer mailing list. If you are unsure which list to use, the cython users list is probably the right one to use, which has the larger audience. There is also a #cython channel on the freenode IRC servers for Cython related chats.
Cython is freely available under the open source Apache 2.0 License.
The latest stable release of Cython is 3.2.9 (released 2026-07-24). Cython is available from the PyPI package index repository.
Core Developers: Stefan Behnel, Robert Bradshaw, David Woods, Matúš Valo, Lisandro Dalcín
Contributors: Marc Abramowitz, Wichert Akkerman, Martin R. Albrecht, Fedor Alekseev, Peter Alexander, Francesc Alted, Somin An, Elliott Sales de Andrade, Ivan Andrus, Michael Anselmi, Arfrever Frehtes Taifersar Arahesis, Takuro Ashie, Phil Austin, Shreyan Avigyan, William Ayd, Josh Ayers, Max Bachmann, Haoyu Bai, Grant Baillie, Nicolas Barbey, Gustavo Sverzut Barbieri, Christopher H. Barker, Richard Barnes, David Barnett, Christopher Bartak, Álvaro Abella Bascarán, Andrea Bedini, Ian Bell, Oscar Benjamin, Sebastian Berg, Jonas Bernoulli, Janek Bevendorff, Aditya Bhosale, Denis Bilenko, Bryan Bishop, Charles Blake, Chuck Blake, Max Bohnet, Guro Bokum, Bertrand Bordage, Alexey Borzenkov, Georg Brandl, Matthias Braun, Volker Braun, Nils Braun, Erik M. Bray, Erik Bray, Matthew Brett, Marcus Brinkmann, Jordan Brière, Spencer Brown, Andrew Brown, Michael Buesch, Lars Buitinck, Evgeni Burovski, Matthias Bussonnier, Corentin Cadiou, Guilherme Caminha, Josiah Carlson, Brandon Casey, Thomas A Caswell, Vladimir Cerny, Ondrej Certik, Matthew Chan, Shalabh Chaturvedi, Chia-Hsiang Cheng, Yuriy Chernyshov, Tasha Ren Chin, Eric Chlebek, David Christenson, Tzu-ping Chung, Craig Citro, James Clarke, B. Clausius, Christian Clauss, Alyssa Coghlan, Maximilien Colange, Samuel Colvin, Alexander Condello, Ludovic Cotterousse, David Cournapeau, Andreas van Cranenburgh, Armon Dadgar, Björn Dahlgren, Jeppe Dakin, Gerald Dalley, Thijs Damsma, Rajat Dash, Gabi Davar, Julien Delafontaine, Vincent Delecroix, Jeroen Demeyer, Michael V. DePalatis, Orivej Desh, Didier Deshommes, Eric Dill, Ulrich Dobramysl, Roman Donchenko, Egor Dranischnikow, Jon Dufresne, Nicolas Dumazet, Frederik Dyrmose, Ali Ebrahim, Matthew Edwards, John Ehresman, Eddie Elizondo, Sean Enck, Raffi Enficiaud, Michael Ensslin, Gerion Entrup, Yuri Escalianti, Loïc Estève, Jason Evans, Kenrick Everett, Gregory Ewing, Curtis Faith, Thomas J. Fan, Matthew Feickert, Yu Feng, Thomas Fenzl, Isuru Fernando, Ioannis Filippidis, Boris Filippov, Segev Finer, Eric Firing, Mark Florisson, Claudio Freire, Danilo Freitas, Jason Fried, Bradley M. Froehle, Gary Furnish, Syam Gadde, Martín Gaitán, Pablo Galindo, Víctor Molina García, Tim Gates, Gabriel Gellner, Julian Gethmann, Pierre Glaser, Igor Gnatenko, Prakhar Goel, Christoph Gohlke, Nathan Goldbaum, Evgeny Golyshev, Ralf Gommers, Mike Graham, Brian Granger, Robert David Grant, Olivier Grisel, Sam Gross, Christoph Groth, Moritz Groß, Charles Grunwald, Candide Guevara, Adrien Guinet, Chris Gyurgyik, Michał Górny, Hans Moritz Günther, Valentin Haenel, Yaroslav Halchenko, Luke Hamburg, Richard Hansen, Tao He, Tong He, Jonathan Helgert, Michael Helmling, Alex Henrie, Ian Henriksen, Philip Herron, Noam Hershtig, Magnus Lie Hetland, David Hirschfeld, Cheuk Ting Ho, Ewout ter Hoeven, Wieland Hoffmann, Till Hoffmann, Clemens Hofreither, Chris Hogan, Elisha Hollander, Myles Hollowed, Jackson Howard, Tomáš Hrnčiar, Miro Hrončok, Jiajun Huang, Nicolas Hug, Thomas Hunger, Eric Huss, Alex Huszagh, Julien Jerphanion, Joe Jevnik, Eric T. Johnson, Matthew Johnson, Pierre Jolivet, Andrew V. Jones, Søren Fuglede Jørgensen, Dmitry Kalinkin, Ivan Kapeykin, Igor Kaplounenko, Omer Katz, Hugo van Kemenade, Karl Kempe, Rafe Kettler, Jerome Kieffer, W. Trevor King, John Kirkham, Jim Kleckner, Thomas Kluyver, Felix Kohlgrüber, László Kiss Kollár, Mike Kolupaev, Liguo Kong, Mikhail Korobov, Sebastian Koslowski, Kacper Kowalik, Taras Kozlov, Anselm Kruis, Jakub Kulík, Patrick Kunzmann, Matěj Laitl, Ronan Lamy, Torst