Python Import Cost
Displays the disk size and import time of every Python package inline in the
editor — right next to the import statement, as you type.
Inspired by the original Import Cost extension for JavaScript.
How it works
The extension scans your file for import statements and runs two lightweight checks per package:
- Disk size — resolved via
importlib.metadata, the same mechanism pip uses internally.
- Import time — measured with
python -X importtime, capturing cold-start latency.
Results are colour-coded and displayed as inline ghost text. Everything is cached per package
and per interpreter, so the editor stays fast after the first analysis.
Requirements
- Python 3.8+
- The Python extension
is recommended for accurate interpreter and virtualenv detection, but not required.
Settings
| Setting |
Default |
Description |
pythonImportCost.showSize |
true |
Show disk size inline |
pythonImportCost.showImportTime |
true |
Show import time inline |
pythonImportCost.sizeWarningThresholdKb |
1024 |
KB threshold for medium (yellow) |
pythonImportCost.sizeDangerThresholdKb |
5120 |
KB threshold for large (red) |
pythonImportCost.timeWarningThresholdMs |
100 |
ms threshold for medium (yellow) |
pythonImportCost.timeDangerThresholdMs |
500 |
ms threshold for large (red) |
pythonImportCost.debounceMs |
500 |
Delay after last keystroke before analysis runs |
pythonImportCost.cacheSize |
200 |
Max cached results held in memory |
Colours can be overridden in your theme via the pythonImportCost.small,
pythonImportCost.medium, and pythonImportCost.large colour contributions.
Commands
Python Import Cost: Clear Cache — forces a fresh analysis on the active file.
Contributing
$ git clone https://github.com/Alkhemrt/python-import-cost.git
$ cd python-import-cost
$ npm install
$ code .
Hit F5 to launch the extension in a VS Code Extension Development Host.
$ npm run compile # one-off build
$ npm run watch # watch mode
$ npm run lint # lint
$ vsce package # produce .vsix
License
MIT
