cffi
Foreign Function Interface for Python calling C code.
Decision gist · record as of 2026-08-14
Yes. CFFI is actively maintained, widely used (top 100 PyPI), carries no security vulnerabilities, and has a permissive license. Install friction is moderate but manageable with prebuilt wheels for all major platforms. It's the right choice if you need to call C code from Python.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.10 or later; pycparser must be available as a runtime dependency.
- Medium install friction due to compiled wheels across many platforms; actively maintained with release 11 days ago and ongoing commits; requires Python 3.10 or later.
License · maintenance · safety
MIT-0 (permissive) — MIT-0 (permissive) license places no restrictions on use, modification, or distribution.
last release 2026-08-03 (11 days) · last repo commit 2026-08-03 · 275 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 1,303,772,314 downloads/mo, #12 on PyPI
Alternatives
Verify before relying
pip install cffi
from cffi import FFI
ffi = FFI()
ffi.cdef("int add(int a, int b);")
C = ffi.dlopen(None)
result = C.add(2, 3)- Whether pycparser is automatically installed as a dependency or must be installed separately
- Performance characteristics compared to alternative approaches
- Support for C++ code or only C
What it is and what it does
CFFI is a Foreign Function Interface library that lets Python code call C functions without writing C extension modules. It works by parsing C declarations you provide and generating the necessary glue code to bridge Python and C, handling type conversions and memory layout automatically. The package depends only on pycparser for parsing C syntax.
Typical use involves declaring C function signatures in Python, then calling them as if they were Python functions. CFFI supports both ABI mode (calling existing compiled libraries) and API mode (embedding C code). It's widely used in domains where performance-critical C libraries need to be accessible from Python.
Use it for
- Wrap existing C libraries for use in Python without writing C extensions
- Call performance-critical C functions from Python while maintaining readable calling conventions
- Embed C code snippets directly in Python projects for tight integration with compiled dependencies
- Build bindings for scientific or numerical libraries originally written in C
- Prototype C interoperability quickly without the overhead of writing full C extension modules
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
CFFI is actively maintained, widely used (top 100 PyPI), carries no security vulnerabilities, and has a permissive license. Install friction is moderate but manageable with prebuilt wheels for all major platforms. It's the right choice if you need to call C code from Python.
Install
cffi on PyPI
Before you install
Medium install friction due to compiled wheels across many platforms; actively maintained with release 11 days ago and ongoing commits; requires Python 3.10 or later.
Requires Python 3.10 or later; pycparser must be available as a runtime dependency.
License in practice
MIT-0 (permissive) license places no restrictions on use, modification, or distribution.
Quickstart
pip install cffi
from cffi import FFI
ffi = FFI()
ffi.cdef("int add(int a, int b);")
C = ffi.dlopen(None)
result = C.add(2, 3)Verify before relying
- Whether pycparser is automatically installed as a dependency or must be installed separately
- Performance characteristics compared to alternative approaches
- Support for C++ code or only C
Package facts
| License | MIT-0 permissive |
| Python support | Supports the current Python release >=3.10 |
| Install friction | Medium. Platform-specific wheel |
| Runtime dependencies | 1 packagepycparser |
| Maintenance | Actively maintained 11 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 1,303,772,314 / month, #12 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Programming Language :: PythonProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: 3.15Programming Language :: Python :: Free Threading :: 2 - BetaProgramming Language :: Python :: Implementation :: CPython |
Evidence: cffi-2.1.1-cp310-cp310-macosx_10_15_x86_64.whl; cffi-2.1.1-cp310-cp310-macosx_11_0_arm64.whl; cffi-2.1.1-cp310-cp310-manylinux1_i686.manylinux2014_i686.manylinux_2_17_i686.manylinux_2_5_i686.whl; cffi-2.1.1-cp310-cp310-manylinux2014_aarch64.manylinux_2_17_aarch64.whl; cffi-2.1.1-cp310-cp310-manylinux2014_ppc64le.manylinux_2_17_ppc64le.whl; cffi-2.1.1-cp310-cp310-manylinux2014_s390x.manylinux_2_17_s390x.whl; cffi-2.1.1-cp310-cp310-manylinux2014_x86_64.manylinux_2_17_x86_64.whl; cffi-2.1.1-cp310-cp310-musllinux_1_2_aarch64.whl; cffi-2.1.1-cp310-cp310-musllinux_1_2_i686.whl; cffi-2.1.1-cp310-cp310-musllinux_1_2_x86_64.whl; cffi-2.1.1-cp310-cp310-win32.whl; cffi-2.1.1-cp310-cp310-win_amd64.whl; cffi-2.1.1-cp311-cp311-macosx_10_15_x86_64.whl; cffi-2.1.1-cp311-cp311-macosx_11_0_arm64.whl; cffi-2.1.1-cp311-cp311-manylinux1_i686.manylinux2014_i686.manylinux_2_17_i686.manylinux_2_5_i686.whl; cffi-2.1.1-cp311-cp311-manylinux2014_aarch64.manylinux_2_17_aarch64.whl; cffi-2.1.1-cp311-cp311-manylinux2014_ppc64le.manylinux_2_17_ppc64le.whl; cffi-2.1.1-cp311-cp311-manylinux2014_s390x.manylinux_2_17_s390x.whl; cffi-2.1.1-cp311-cp311-manylinux2014_x86_64.manylinux_2_17_x86_64.whl; cffi-2.1.1-cp311-cp311-musllinux_1_2_aarch64.whl
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