less median time to an editable standalone file than same-revision Code-OSS
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 and dials back the stuff that tries to grab your attention.
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 to an editable file in a 10,000-file Git repository
less median time from app launch to a local Git diff returned for review
less median time from app launch to the first edit saved and verified on disk
On an Apple M3 Max, signed Lean v0.4.0 reached an editable standalone file in 1.421 s median / 1.483 s p95 versus 1.715 / 1.776 s for original Code-OSS 1.139.1 at the fork's upstream base revision. In a separate 10,000-file Git repository, the medians were 1.482 s versus 1.827 s, with p95 of 1.687 s versus 2.180 s. From a stopped app to the bundled Git extension returning a local diff, medians were 1.497 s versus 1.906 s, with p95 of 1.672 s versus 2.105 s. From a stopped app to an edit saved and verified on disk, medians were 1.425 s versus 1.901 s, with p95 of 1.693 s versus 1.946 s. Each workload used 30 alternating warm-cache launches per app with isolated profiles. Both apps were minified; Code-OSS was a locally repaired source build, not the official VS Code distribution. Git diff retrieval is not a painted diff editor, and Lean's Git action and saved-edit p95 after startup were slower. Search and terminal exploratory trials did not establish a Lean speed advantage, and idle-memory readings varied between runs; no lower-memory claim is made. See raw results and the method
The release reached the editable file about 295 ms sooner in the standalone trial, 345 ms sooner in the Git-repository trial, the local Git diff about 409 ms sooner from launch, and a verified saved edit about 476 ms sooner than original Code-OSS, at the median. Editing, search, terminal, Git review, and extensions remain available.
A DEVELOPER'S YEAR
Small waits add up.
5.75 hours
illustrative saving versus the Code-OSS source baseline
In the past year, Matti's ILOapps commits touched more than 70,000 files. In the matched-build v0.4.0 benchmark, Lean reached an editable file 295 ms sooner than the same-revision Code-OSS source build at the median. That would add up to about 5.75 hours if the app started separately for every file touch. The goal of saving a full second per launch would mean about 19.4 hours per 70,000 starts; that goal has not yet been measured.
Illustration: 70,276 file touches × 0.2945 seconds ≈ 5.75 hours. Both benchmark apps were minified; the Code-OSS comparator was a locally repaired source build, not an official VS Code distribution. The benchmark measures fresh app startup, not annual time saved; existing-window file opens follow another path. Git history covers 95 local ILOapps repositories, 26 September 2025–26 September 2026, and 14,206 Matti-authored non-merge commits across 39 active repositories. Repeated changes to a file count again; 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 turns off unsolicited AI prompts, recommendations, experiments, and telemetry 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 the project story on GitHubMADE 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. v0.3.2 can update to v0.4.0; v0.3.0 and the withdrawn v0.3.1 candidate need a manual install of v0.3.2 or newer once.