less median time to an editable file with extension support in a minified v0.6.0 candidate trial
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.
See benchmark results and how we measured
On an Apple M3 Max, the minified v0.6.0 candidate reached an extension-backed editable 100 KiB file in 1.307 s median / 1.427 s p95 versus 1.637 / 1.785 s for the original, same-revision minified Code-OSS source build. In a separate signed v0.6.0 trial, a first edit saved and verified on disk took 1.468 / 1.912 s versus 1.959 / 2.640 s from app launch. The saved-edit action alone was slower in Lean (86.3 versus 43.3 ms median); the gain is in the whole launch-to-save workflow. With an established profile opened through macOS LaunchServices, a synthetic first UI edit took 0.982 / 1.054 s versus 1.205 / 1.641 s. Each endpoint used 30 alternating pairs with no failed timed samples in these headline runs. The extension-backed and Finder results are from the unsigned minified candidate; the saved-edit and bundle results are from the final signed app.
The first UI edit is synthetic input verified in Monaco, not a physical keypress or display-photon timestamp. The extension-backed test confirms a reversible edit probe, while the saved-edit test confirms bytes on disk. Profiles and completion events differ, so these percentages are separate workloads. Both apps came from the same Code-OSS 1.139.1 source revision; the comparator is a locally repaired source package, not Microsoft's VS Code distribution. The sub-second p95 first-edit goal remains open.
Earlier signed v0.4.0 trials against original Code-OSS measured 19% less median time to an editable file in a 10,000-file Git repository, 21% less time from launch until a local Git diff was returned, 25% less time to verified workspace text-search results, and 13% less time to a verified terminal command result. These are historical v0.4.0 results, not new v0.6.0 measurements.
LESS TO CARRY
Less on disk.
Lighter at idle.
smaller installed app bundle in signed v0.6.0 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 v0.6.0 app contains 535 MiB of apparent file content versus 1,463 MiB for the original comparator, 63.4% less. This size is measured against a locally repaired, minified original Code-OSS 1.139.1 source package on the same Mac. The percentage is an app-bundle comparison, not a DMG download-size or runtime-memory result. The app ships 33 bundled extensions; optional installed extensions can add disk use.
The memory figure is from signed v0.4.0, not a new v0.6.0 claim. In nine independent alternating short-idle pairs, its app-tree median was 655 MiB versus 786 MiB for original Code-OSS after 30 seconds idle. The current v0.6.0 one-launch GPU samples varied too much to support a new memory percentage. These footprints do not predict 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 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. v0.5.0 can update to v0.6.0; v0.3.0 and the withdrawn v0.3.1 candidate need a manual install of v0.3.2 or newer once.