less median time to an extension-editable file from launch in signed v0.10.0
A CALMER CODE-OSS EDITOR
A quieter place
to write code.
Open a project. Write code. Review your changes. Lean VS Code keeps the familiar tools, supports extensions, and leaves built-in AI panes out of your way.
The editor, editing its own source. Take a closer look by opening the image.
MEASURED AGAINST ORIGINAL CODE-OSS
Less waiting.
More flow.
less median time from launch to a first edit saved and verified on disk in signed v0.6.0
less median time from a Finder launch to a first synthetic UI edit in a minified v0.6.0 candidate trial
Open a file, make a change, and get back to your project. Lean keeps editing, search, terminal, Git review, and extensions while leaving built-in AI panes out of the workbench. Read what the speed results do and do not show →
See benchmark results and how we measured
On an Apple M3 Max, signed v0.10.0 reached an extension-editable 100 KiB file in 1.471 s median / 1.596 s p95 versus 1.903 / 2.141 s for original same-revision Code-OSS. The 30 alternating fresh-profile pairs had no failed timed samples. An existing-window file open was 416 versus 403 ms median, a small Lean regression. The p95 startup goal of less than one second remains open.
The saved-edit figure comes from a separate signed v0.6.0 trial: 1.468 versus 1.959 s from launch to bytes verified on disk. Its edit/save action alone was slower in Lean. The Finder figure comes from an unsigned v0.6.0 candidate with established profiles and synthetic UI input. These are separate workloads, not current-release speed results. The comparator is a locally repaired, minified Code-OSS 1.139.1 source build, not Microsoft's VS Code distribution; extension editability is not physical screen paint.
Other historical signed v0.4.0 trials measured Git review, workspace search, and terminal workflows. The raw reports include their exact versions and methods.
LESS TO CARRY
Less on disk.
Lighter at idle.
smaller installed app bundle in signed v0.10.0 than original, same-revision Code-OSS
lower median short-idle footprint in a separate signed v0.4.0 trial versus original Code-OSS
See size and memory methods
The signed v0.10.0 app contains 514 MiB of apparent file content versus 1,463 MiB for a locally repaired, minified original Code-OSS 1.139.1 source package: 64.9% less. This is an app-bundle disk comparison, not a DMG download-size or runtime-memory result. Installed extensions add their own files.
The headline memory figure is from signed v0.4.0: 655 versus 786 MiB median in nine independent short-idle pairs, with Lean lower every time. A new signed v0.10.0 nine-pair trial measured 395 versus 524 MiB median, but 3 pairs favored Code-OSS as GPU footprint modes varied. Neither result predicts peak or long-session use.
A DEVELOPER'S YEAR
Small waits add up.
9.6 hours
illustrative saving versus original Code-OSS
A first edit saved to disk was 491 ms sooner from app launch in the signed v0.6.0 paired trial. Across 70,276 file touches, that would add up to about 9.6 hours if each touch started a fresh app and saved an edit. It illustrates the size of a small repeated wait; it is not observed time saved.
See the calculation and assumptions
70,276 × (1.959 − 1.468) seconds ÷ 3,600 ≈ 9.6 hours. The paired v0.6.0 result measures a fresh process opening a one-file Git fixture, making a first edit, saving it, and verifying the bytes on disk. It does not describe ordinary edits inside a running window. The Code-OSS app was a matched, locally repaired source build. The annual file-touch count comes from Matti's ILOapps commits from 26 September 2025 to 26 September 2026; repeated changes count again, while dependency/build paths and commits touching more than 100 files were excluded.
THE GOOD PARTS STAY
Your workflow already fits.
Get straight to the work
Files, project search, the integrated terminal, and local Git review are ready when you need them.
Choose your extras
A smaller set of extensions comes built in. Find more through Open VSX or install a local VSIX.
Keep your setup separate
Lean VS Code has its own app identity, settings, and extensions, so it can sit beside VS Code.
WHY THIS FORK EXISTS
Sometimes you just want to open a folder and code.
Code-OSS is a great foundation. Lean VS Code is a take on what happens when the editor puts writing code and reviewing local changes first.
It ships with fewer built-in extensions and no built-in chat or agent interface. Recommendations, experiments, and telemetry are off by default. Signed app updates from GitHub are the one background check enabled by default; you can change when Lean VS Code checks in Settings. The editor and extension platform are still there; you decide what to add.
Read why this exists →MADE FOR THE EVERYDAY LOOP
See what changed.
Keep moving.
Inspect local Git changes side by side in the familiar diff view, then get back to your code.
See the open-source project
READY TO TRY IT?
Open the project.
Get to work.
Download the signed, notarized DMG from GitHub and drag Lean VS Code into Applications. The current release is for Apple Silicon Macs.
Starting with v0.3.2, Lean VS Code checks for signed macOS updates and offers Restart to Update when one is ready. v0.10.3 can retry through the GitHub API when the normal download fails. If an older version cannot update, install the latest DMG over the existing app.
THE LEAN FAMILY
Meet Lean Term.
A focused terminal for macOS, from the same Lean family. In development