Open files in VS Code and Cursor / Machine learning files

Open a .pkl pickle file in VS Code without running it

Loading a pickle with Python can run code that is inside the file. The free Pickle Viewer & PKL Viewer by Zovo reads .pkl and .pickle files without Python and without running anything. It shows the data as a tree, NumPy arrays with stats, pandas DataFrames as tables, the opcodes, and a Safety tab that lists every call the pickle would make.

Install in VS Code Marketplace page Open VSX (Cursor, Windsurf, VSCodium)

Free, MIT license. Extension ID zovo.zovo-pickle-viewer, version 0.1.4. Needs VS Code 1.90.0 or newer.

The Safety tab flagging os.system in a pickle.

Steps in VS Code

Install Pickle Viewer & PKL Viewer from the Marketplace, or press Ctrl+P (Cmd+P on macOS) and run ext install zovo.zovo-pickle-viewer.
Click a .pkl or .pickle file. For .p files, right-click and pick "Open in PKL Viewer".
Read the Tree tab. Classes that need their package show as module.Class placeholders.
Open Arrays for NumPy data and Tables for pandas DataFrames.
Check the Safety tab. A red banner opens it for you when a file calls something risky such as os.system.

Steps in Cursor, Windsurf or VSCodium

Open the Extensions view with Ctrl+Shift+X (Cmd+Shift+X on macOS).
Search for zovo.zovo-pickle-viewer and click Install. Cursor, Windsurf and VSCodium install from Open VSX, where it is published as zovo/zovo-pickle-viewer.
If your editor has no gallery, download the .vsix from the Open VSX page and run "Extensions: Install from VSIX...".
Then use it the same way as in VS Code.

What Pickle Viewer & PKL Viewer handles

Pickle protocols 0 to 5, NumPy 1.x and 2.x, pandas 2.x and older layouts.
Ratings for every call: Risky, Check, Needs package and Data type.

What it does not do

A clean Safety list is not a promise that a file is safe. Only load pickles you trust in Python.
Files over 512 MB show a message. Containers show their first 1,000 items and tables their first 1,000 rows.
PyTorch .pt archives and joblib files with compressed arrays do not open here. Use Tensor Viewer for .pt files.

Other options

PKL Viewer (alarm.pkl-viewer, 26,801 installs, on Open VSX). A different extension with a similar name. Its own description: "View Python pickle (.pkl) files directly in the VS Code editor."
pickle-viewer (SDPolite.pickle-viewer, 9,859 installs, not on Open VSX). Another pickle viewer. Not on Open VSX.
pickletools. python -m pickletools file.pkl lists the opcodes without loading the objects.

Install counts and Open VSX status were checked on 8 November 2026. Descriptions in quotes are the extensions' own.

Questions

Is it dangerous to open a pickle file?

Loading it with pickle.load or pandas.read_pickle can run code from the file. Reading it with this viewer does not, because the reader never imports or calls anything.

Do I need Python installed?

No.

Can it open PyTorch .pt files?

No. Tensor Viewer opens those, also without running the pickle.

More about Pickle Viewer & PKL Viewer

Read the Pickle Viewer & PKL Viewer page for every feature and setting, or the source code on GitHub.

Support this work

If this extension saves you time, you can support the work on GitHub Sponsors. Monthly tiers start at $5, and one-time tiers start at $15. Sponsorship is optional, and the tool works the same without it.

Zovo on GitHub