The code editor by Ovear · macOS & Windows

Every change, in harmony.

Harmony is a fast, familiar code editor with a complete Git forge built in, fully offline, and Claude on call when you want it. Your code never leaves your laptop.

Download for macOSUniversal · macOS 13+ Download for WindowsWindows 10 / 11 · 64-bit

or, from a terminal: harmony .

The Harmony workbench: cart.ts open in the editor beside an Explorer, with coloured pin markers in the gutter next to the lines that issues are attached to, and a toast reading “Pinned #5 to cart.ts:38–40”.
fig. 1 — the workbench, with the Hub one shortcut away (⇧⌘H)

One app, three voices

A trio, not a toolbox.

Most teams stitch together an editor, a code host and an AI assistant, then spend their days switching between them. Harmony plays all three parts in one window, on one machine.

  1. The Editor

    The engine inside VS Code, in a calmer room.

  2. The Hub

    Repositories, proposals, issues and releases. No server required.

  3. Claude

    A collaborator that stays off until you invite it.

The Editor

Feels like home on the first keystroke.

Harmony is built on Monaco, the engine inside VS Code, dressed in GitHub’s VS Code colors with an airy islands layout. Your muscle memory comes with you: the same keybindings, the same command palette, the same quick open.

  • Tabs and split editors
  • Command palette and quick open
  • Project-aware TypeScript IntelliSense
  • Search and replace across files
  • An integrated terminal
  • Source Control with a timeline for every file
In the editor, a hover card attached to line 28 of cart.ts reads “Open #2 total() rounds wrongly for EUR (half-cents)”, with bug and good first issue labels and buttons to open it in the Hub or unpin it.
fig. 2 — an issue pinned to the lines it’s about
  • ⌘PQuick open
  • ⇧⌘PCommand palette
  • ⇧⌘HCode ↔ Hub
  • ⌘LClaude chat
  • ⌘\Split editor

⌘ is Ctrl on Windows.

Harmony Hub

Your whole forge. Fully offline.

The Hub is a complete home for your repositories and the people you share them with: files and history, proposals, issues, releases, docs and boards. It runs in an isolated process with no network code at all.

Feature spotlight

The Score

Your branches, drawn as staves. See where work split off, where it came back together, and what’s still in rehearsal.

The Score: three staves on one timeline, one per branch. Feature/cart, the branch you are on, leaves main and merges back, and release v1.4 is marked on main with a double bar line. Fix/login forks off the last feature/cart commit and is still in rehearsal: its last two notes are hollow. main feature/cart fix/login v1.4 The Score: three staves on one timeline, one per branch. Feature/cart, the branch you are on, leaves main and merges back, and release v1.4 is marked on main with a double bar line. Fix/login forks off the last feature/cart commit and is still in rehearsal: its last two notes are hollow. main feature/cart fix/login v1.4
commit in rehearsal release Each branch keeps its own color, as in the app. A hollow note is work still in rehearsal.
The Score view in the Hub: ten branches drawn as horizontal staves with commits as dots, curved lines where branches leave main, proposal brackets such as “#14 Add dark mode”, and a v0.3.0 release tag.
fig. 3 — the Score, in the app
The Hub’s home screen: a greeting, the repositories in progress, six things waiting for you such as proposals ready to merge, the peers you exchange bundles with, and a Safety panel noting that every change can be undone.
fig. 4 — the Hub: today’s work, and what’s waiting for you
A proposal titled “Add dark mode #14” in the Hub, with its description, Discussion, Commits and Changes tabs, and a Readiness panel listing no conflicts, six commits behind main, no approval yet, and a Merge proposal button.
fig. 5 — a proposal, ready to merge

  • Proposals

    Reviews, line comments, a readiness checklist, then merge, squash or rebase.

  • Issues pinned to code

    Select lines, file an issue, and it stays in the gutter next to the code it’s about.

  • Releases and milestones

    Tag versions, write the notes, and track what ships next.

  • Docs and boards

    A versioned wiki and boards that live inside the repository.

  • Plain Git underneath

    Every repository is an ordinary .git folder. Copy the folder and you copy everything.

  • Search everything

    Press / for code, issues, proposals and docs, all from one box.

Fearless by default

Undo anything.

Harmony assumes you’ll make mistakes, and makes them cheap.

The Safety net page in the Hub, headed “Undo anything”: a journal of recent actions such as a commit, a stash, a discard and a hard reset, each with an Undo button, beside saved snapshots with Restore buttons and a list of stashes.
fig. 6 — the Safety net

  1. Safety net

    Every operation that changes a repository is journaled with a one-click Undo. Destructive ones take a full snapshot first.

  2. Rewind

    Every save is kept, 50 versions per file by default, right in the Timeline. Claude’s edits get a “before” point automatically.

  3. Vault

    Mirror every repository to another drive, like a USB disk. Incremental backups, restorable in a click.

Claude

Claude, when you call for it.

Claude is built in and switched off. Turn it on and it joins the session: answering questions about your code, editing files in agent mode with your approval, and drafting the busywork.

  • Chat about any file or selection (⌘L, ⌘I)
  • Agent mode that edits files, only with your approval
  • Inline suggestions as you type
  • One-click commit messages, proposal descriptions and reviews
Claude’s chat panel in agent mode. Asked to fix the off-by-one in the total loop in src/app.ts, Claude reads the file and proposes an edit as a diff marked “Waiting for you”, with Approve and Reject buttons.
fig. 7 — agent mode, waiting for your approval
Off by default
Nothing is sent until you switch Claude on.
Your key, sealed
Stored encrypted by the macOS Keychain or Windows DPAPI.
Every request logged
See what was sent, its size and its token counts.
Your provider
The Anthropic API or Amazon Bedrock.

Claude Opus 5.5 for chat and Claude Haiku 5.5 for inline suggestions, both changeable in settings.

Unison compression

An entire repository. One small file.

A .harmony bundle carries the code, its full history and the Hub (issues, proposals, reviews, docs) in a single file. Hand it over on a USB stick, AirDrop it, attach it to an email. No server, no network, nothing lost.

8.4 times

smaller than git bundle for the full history of Vue core: 7,231 commits, from 35.3 MB of .git folder to a 3.9 MB .harmony file.

Each group is scaled to its own .git folder. “× smaller” compares .harmony with git bundle --all.

Size of the full history of three open-source repositories, in megabytes
RepositoryCommits.git foldergit bundle --all.harmony.harmony compared with git bundle
vue core7,23135.3 MB33.1 MB3.9 MB8.4 times smaller
express6,18210.5 MB9.5 MB2.7 MB3.5 times smaller
requests6,49513.5 MB12.6 MB6.3 MB2.0 times smaller

Full histories of real open-source projects, measured on an M-series Mac. requests shrinks least: the images and test data in its history barely compress.

How Unison works, in three movements

  1. The Lexicon

    Harmony ships with a built-in lexicon of the most common lines of code. Bundles never carry them.

  2. In unison

    Every distinct line that ever existed is stored exactly once. Each version of a file is an edit script over line IDs, newest first, so history costs almost nothing and the latest code reads on its own. Folder trees aren’t stored at all; they’re rebuilt exactly.

  3. The Harmonic Coder

    A context-mixing compressor tuned for source code packs the result on every core, typically 25 to 30% smaller than brotli or xz.

Byte-exact
Every Git object rebuilt exactly. git fsck stays clean.
Incremental
Send a colleague only what they don’t have yet.
Encrypted
Optional password protection with AES-256-GCM.
Mergeable
Diverged work arrives as a proposal, and every import undoes in one click.
The “Share web-app” dialog: choose who the file is for (anyone with a full copy, or a person who only needs what they don’t have yet), choose which branches and tags to include, then save the .harmony file.
fig. 8 — sharing a repository as one .harmony file

In music, unison is many voices on a single note. In Harmony, it’s every copy of a line, stored as one.

Where Harmony plays best

Made for rooms the cloud can’t reach.

  1. Air-gapped and regulated teams

    Defense, healthcare, finance, research labs: get reviews, issues and releases on machines that never touch the internet.

  2. Two people, zero servers

    Pair with a colleague across the desk or across the world. Send an incremental bundle, and diverged work arrives as a proposal to review.

  3. Coding on the move

    Planes, trains, field sites. The whole forge travels with you, so a missing Wi-Fi signal never blocks a review.

  4. Classrooms and workshops

    Hand out a repository with starter code, issues and docs on a USB stick. Collect the work back the same way.

  5. Client handoffs

    Deliver a project with its complete history and the conversations behind it, in one password-protected file.

  6. The privacy-minded developer

    AI on your terms: off until you enable it, with every request logged. The extension registry stays off until you switch it on, too.

The harmony command

Conduct from the terminal.

The harmony command opens files and drives the Hub, the way code does for VS Code. It runs Harmony’s own engine, so it needs no Git and no Node. While Harmony is open, the editor and the Hub update live.

$ harmony .                          # open this folder
$ harmony -g src/app.ts:42:7         # jump to a line and column
$ harmony init                       # first commit, added to the Hub
$ harmony commit -m "Fix the cart"
$ harmony share -o web-app.harmony   # the whole repo, one file
$ harmony receive web-app.harmony    # and back again

Stays on your machine

  • The Hub engine contains no network code.
  • Claude stays off until you turn it on.
  • The extension registry stays off until you switch it on.
  • Harmony warns you when a repository sits in iCloud Drive, OneDrive, Dropbox or Google Drive.

Coda

Take it from the top.

Download Harmony, open a folder, and everything else is already here.

The Harmony app icon
Download for macOS One universal app for Apple Silicon and Intel. Disk image or zip. macOS 13 Ventura or newer. Download for Windows Installer (no admin rights needed) or a portable .exe. Windows 10 and 11, 64-bit.