decompyle3

3.9.3 verified Mon Apr 27 auth: no python

Python cross-version byte-code decompiler targeting Python 3.7-3.8 bytecode. Current version is 3.9.3 (2025). Releases are sporadic, roughly once per year. Requires xdis (6.x) and spark-parser. Supports running on CPython up to 3.13 but only decompiles bytecode up to 3.8.

pip install decompyle3

Common errors

error ImportError: cannot import name 'decompile' from 'decompile3' ↓

cause Mis-typed package name in import (decompile3 vs decompyle3). Note the 'y' in decompyle3.

fix

Use 'from decompyle3 import decompile' (decompyle3 with a 'y').

error ValueError: bad marshal data (unknown type code) ↓

cause Trying to decompile a .pyc file from Python 3.9+ which uses a different magic number and bytecode format.

fix

Only decompile .pyc files generated by Python 3.7 or 3.8. Check Python version with 'head -c 4 file.pyc | od -An -tu4'.

error ModuleNotFoundError: No module named 'xdis' ↓

cause Missing required dependency xdis.

fix

Install xdis: 'pip install xdis'. Make sure you have xdis 6.x.

error AttributeError: module 'xdis' has no attribute 'PYTHON_VERSION' ↓

cause Incompatible xdis version (e.g., xdis 5.x instead of 6.x).

fix

Upgrade xdis to version 6.x: 'pip install "xdis>=6,<7"'.

error RuntimeError: Unsupported Python version 3.9 ↓

cause decompyle3 cannot decompile bytecode from Python 3.9+.

fix

Use a different decompiler for Python 3.9+ (e.g., uncompyle6 does not work either; try pycdc or wait for decompyle3 updates).

Warnings

breaking decompyle3 only decompiles Python 3.7 and 3.8 bytecode. It cannot decompile bytecode from Python 3.9+. ↓

fix Use uncompyle6 for Python 2.7-3.8, or try pycdc/decompyle3-fork for newer bytecode.

gotcha The package requires xdis version 6.x, which may conflict with other tools that require xdis 5.x or 4.x. ↓

fix Use a virtual environment to isolate decompyle3 from other projects with different xdis requirements.

gotcha Command-line tool is `decompyle3`, not `decompyle`. Running `decompyle` will fail with 'command not found'. ↓

fix Install and run `decompyle3 filename.pyc`.

deprecated Support for Python 2.x has been removed. Use uncompyle6 for Python 2.7. ↓

fix Install uncompyle6 for Python 2 decompilation.

Imports

decompile
```
from decompyle3 import decompile
```
main entry point
decompile_file
```
from decompyle3 import decompile_file
```
decompile a .pyc file to string

Quickstart

Decompile a .pyc file to stdout. Requires Python 3.7-3.8 bytecode.

from decompyle3 import decompile_file
import sys
# Decompile a .pyc file and print source
out = sys.stdout
with open('example.pyc', 'rb') as fp:
    decompile_file(out, fp)