Bow

An open-source browser in the spirit of Arc, for macOS.
Tabs in a vertical sidebar, Spaces, Favorites, Peek, Split View, Little Windows and tabs that tidy themselves away.

Download for Mac · Features · Build it yourself · Contribute

Why Bow

Arc is being shut down. Bow keeps the way of browsing that made it special: the sidebar is your whole browser, every Space has its own colours and tabs, and tabs you stop using move to the archive by themselves. Bow is built with Electron and TypeScript, so every page runs on Chromium, and Chrome extensions work.

Before Arc goes, we studied how it behaves (from its app bundle and the files it writes; see docs/research) and rebuilt that behavior in our own code. No Arc code or assets are used; the one exception is the importer, which shows each browser's own logo (Arc's included) only to name the browser an import comes from (sources). Bow is not affiliated with or endorsed by The Browser Company; Arc and Dia are their products and trademarks. (A bow is another word for an arc.)

Command Bar (⌘T): open tabs, history, search and browser actions.	Split View: drop a tab on another tab to put them side by side.
Spaces: each with its own theme, pinned tabs and profile.	Light and dark: a Space's theme colours the whole window.

Install

1. Download Bow-…-arm64.dmg from the latest release. Bow runs on Macs with Apple silicon (M1 or newer) and macOS 13 or later.
2. Open the disk image and drag Bow to Applications. Bow is signed and notarized by Apple, so it opens without warnings.
3. To make it your everyday browser, choose Bow › Set as Default Browser… (or type "default" in the Command Bar), or pick Bow in System Settings › Desktop & Dock › Default web browser. Links and HTML files from other apps then open in a Little Window, or in a Space when an Air Traffic Control rule matches.

Coming from Arc? File › Import from Arc… reads Arc's files on this Mac (read-only) and adds your Spaces, Favorites, pinned folders and tabs, Today tabs, Space themes, Arc's cached icons, your archive (newest 250), your browsing history and your Chrome Web Store extensions (copied, so they survive Arc; each keeps the on/off it had in Arc). Running it twice adds nothing twice. Chrome, Brave, Edge, Vivaldi, Firefox and Safari can be imported too (Library › Settings).

Never locked in. File › Export Bow Backup… writes everything that makes your setup yours (Spaces, pinned tabs and folders, Favorites, Today tabs, Notes, Easels, Boosts, Air Traffic Control rules and settings) to one open JSON file (format). File › Restore from Backup… puts a backup in place of your setup (Bow keeps a copy of the current one first) or adds its Spaces next to yours. A restored file is checked like untrusted input: only web, note and easel addresses get in, and JavaScript Boosts arrive switched off. While Bow is in use, it also keeps automatic copies every hour (the last 12 hours, then one a day for a week) in its Backups folder, where Restore… opens; Library › Settings › Backup turns them off.

Sync without an account. Library › Settings › Sync › Choose Folder… syncs Spaces, pinned tabs, folders, Favorites, Notes, Easels, Boosts and rules between your Macs through a folder they all reach, such as iCloud Drive or Dropbox. Each Mac keeps one file there and reads the others'; a change merges piece by piece, so renaming a tab on one Mac and pinning a page on another keeps both. Today tabs, the Archive and settings stay on each Mac (how it works).

Bow keeps itself up to date: a few times a day it looks for a new release here on GitHub, downloads it in the background, and the sidebar says Update ready. Click Restart, or just quit Bow; the new version is there the next time it opens. Bow › Check for Updates… looks right away. The check downloads a small file from this repository's releases and sends nothing about you.

Build it yourself

nvm use        # Node 24 (see .nvmrc)
npm install
npm start      # builds, then opens Bow
npm test       # unit tests (Vitest)
npm run e2e    # drives the real app with Playwright (opens windows for a few minutes; throwaway profiles)

npm run package builds release/Bow-darwin-arm64/Bow.app, signed ad hoc for your own Mac. npm run release builds a release's files: the signed, notarized disk image, the zip and the feed that installed copies update from (it needs a Developer ID certificate and notarytool credentials; see the top of tools/release-mac.sh). A build from source never updates itself.

What works

Sidebar

• Favorites as tiles at the top, kept per Space, so two Spaces with the same profile can have different rows (up to 12 each). The selected one gets a border in the colour that appears most in its icon, like Arc's.
• A Space title (click to collapse Pinned), Pinned tabs and nested folders, a divider with Clear, + New Tab, and the Today list. A closed folder still shows the tab you are on.
• A Pinned tab that left its page shows Arc's "/" (its menu has Back to Pinned URL). ⌘W on a Pinned tab puts its page away but keeps the tab.
• Drag and drop: reorder, pin, make a Favorite, drop into a folder, move to another Space, drop a tab on another tab to put them side by side, or drop a link to open it.
• Bottom bar: Library, the Space switcher (emoji for the active Space, dots for the others), and a + menu.
• ⌘S hides the sidebar; touching the window's left edge shows it again for a moment, as a floating panel like Arc's. Drag its edge to resize it. Icons fade while the window is in the background, text does not (Arc's look).
• Compact Mode (⌥⌘S) hides the sidebar and the toolbar (⇧⌘D hides only the toolbar): touching the window's left edge slides the sidebar in, its top edge the toolbar. Focus Mode (⇧⌘F) shows only the page, filling the window, until ⇧⌘F again. Each window has its own.
• A dot on a Pinned tab or Favorite whose page changed while you were elsewhere (a new mail count), like Arc.
• Notes on tabs and folders (their menu › Add Note…): a line of your own under the title, such as "Read before Friday", written in place; the whole note shows when you rest the pointer on the row.
• A small player for a tab playing sound in the background.
• Rest the pointer on a tab for Arc's tooltip (its title; "Double-click to rename" on the selected tab); ⌃Tab shows the recently used tabs as cards with pictures.
• Rest the pointer on a closed folder to see its tabs beside it, newest first ("1 minute ago"), with a search field, like Arc; click one to open it.
• Pinned tabs show tidy titles ("Inbox" rather than "(3) Inbox - Mail"), our own rules (Library › Settings).
• Live folders (+ › New Live Folder) fill themselves, like Arc's: your open GitHub pull requests, review requests, assigned issues, issues you opened or notifications (read from github.com with the Space's own GitHub sign-in: no token, private repositories included); the issues of the Jira filter or Linear list on screen (Issues from This Page, read the same way with your sign-in there); the posts of the page's RSS/Atom feed (a subreddit works too), or Hacker News in one click. They refresh every 10 minutes; a folder that needs you to sign in says so and refills once you visit the site; new items get a dot, items you remove stay hidden (folder menu › Show Removed Items), the page you are reading never disappears. An Arc import keeps Arc's GitHub live folder live.
• Like Arc, the frame is darker while the window is active and lighter grey in the background (measured on the real screen against the user's Arc).
• The look is measured from Arc pixel by pixel (node e2e/arc-compare.mjs puts them side by side): Apple's SF Symbols, Arc's frame colors from a Space's theme and intensity, the toolbar inside the page card tinted with the page's own color, and motion that glides (the page moves with the sidebar).

Spaces and profiles

• Create, rename, change the icon (Space menu › Change Space Icon…: Arc's popover over the Space's button, with an Emoji tab and an Icon tab of SF Symbols), edit the theme (Space menu › Edit Theme…: Arc's popover beside the sidebar's bottom, a dotted pad with one handle per color (up to three), automatic / light / dark, preset colors, an intensity slider and a grain dial), reorder, delete. Two-finger swipe on the sidebar or ⌃1–⌃9 switches Spaces.
• Each profile has its own cookies and logins (an Electron session partition). Space menu › Profile moves a Space to another profile or a new one.
• Each Space can have its own defaults (Space menu): Search Engine (Work searches with Google, the rest with DuckDuckGo) and New Tab Opens a page of its own (Use Current Page) instead of the Command Bar; ⌘L still opens the Command Bar there. They stay on each Mac, like the Space's archive timing.
• Space templates: Space menu › Save as Template keeps the Space's icon, theme, Pinned tabs and folders (a live folder keeps its source and fills itself again) and its own defaults; + › New Space from Template (or the Command Bar, or Library › Spaces) makes a new Space like it with fresh tabs. Notes and Easels are left out; templates are in backups and sync between your Macs.
• Private windows (⇧⌘N) keep nothing: an in-memory session, no history, no archive.

Windows

• File › New Window (⌘N) opens another full window, like Arc: the same Spaces, Favorites, Pinned and Today lists, but its own Space and its own selected tab in each Space. It opens on the Space you were in, with the Command Bar ready for a new tab.
• Each window has its own sidebar, like Arc: ⌘S, its width, and which Pinned sections and folders are open. A new window starts with the sidebar of the last window you closed (Arc's rule), and the folders of the window it came from.
• A page is on screen in one window at a time. Selecting a tab another window shows says "Open in another window", with Move to This Window. Notes and Easels too: one window edits them at a time, and moving one over keeps the last keystrokes.
• Drag a tab, folder or split from one window's sidebar into another's (Favorites, Pinned, Today, a folder, next to a split, or a Space button). A tab or split comes along: the other window selects it and its page moves over; the window it came from shows another of its tabs. On a Space button it only moves to that Space.
• Menus, shortcuts, the Command Bar, the Library, Peek and the other panels act in the window in front. ⇧⌘W closes a window; the app quits with the last one. Every window (place, size, Space, selection) opens again at the next start; links from Little Windows go to the main window you used last.

Command Bar (⌘T, ⌘L)

• Finishes addresses as you type ("git" → github.com, also well-known sites you never visited).

• Open tabs ("Switch to Tab"), history, what you typed, search suggestions and about 40 browser actions ("New Space", "Toggle Sidebar", "Copy URL", "Theme: Mint", …), ranked by how well title and address match plus boosts for open tabs, Favorites and recent use, the way Arc ranks.

• Recently closed: with nothing typed, the 3 tabs you closed last are listed below the recent ones; a closed tab that matches what you type is offered too. Return reopens it where it was (like ⇧⌘T, for any of them).

• History by date: type "yesterday", "monday", "last friday", "3 days ago", "this week" or "last week", alone or with words ("yesterday github"), for the pages you visited then, newest first, with the time of each visit.

• Chains (Library › Chains): several actions and pages in one command. Build "Morning" from "Switch to Work", "Open github.com/notifications" and "Toggle Sidebar", then type "morning" in the Command Bar to run them in order. A chain never runs another chain; chains are in backups and sync between your Macs.

• Answers: a sum ("12*7", "(3+4)^2", "sqrt(2)", "15%") or a unit conversion ("5 km in mi", "350 f to c", "2 cups in ml", "1 GiB in MB", "100 km/h to mph") is worked out on top as you type; Return copies the answer. Worked out on your Mac, so the text is not sent to the search engine (no currencies: their rates would need a server).

• Tab to search a site: type "youtube" (or "wiki", "gh", "maps", "claude", …), press Tab, type your search, Enter. Backspace in the empty field goes back. The sites and their search addresses are listed in src/shared/siteSearch.ts.

Pages

• Reader view (⌃⌘R, or the toolbar's page button on articles): the article without the site around it (menus, ads, sidebars, language lists, tables of contents, infoboxes) in one calm column under its title, shown once, with its site, author and reading time; A− / A+ size the text, Escape or Done goes back to the page, which stayed loaded where it was. Bow's own extraction: the page's text comes in as plain text, never as markup.
• Peek: a link from a Pinned tab or Favorite to another site, or any Shift-clicked link, opens in a card that hangs from the window's top edge with its own back / forward / reload row, the page behind dimmed, like Arc's. ⌘O (or the round ↗ button) makes it a tab without reloading, Split puts it next to the page, Esc closes it.
• Split View: two to four tabs side by side, stacked, or in a 2×2 grid, one row in the sidebar. Drop a tab on the middle of another tab (or ⌃⇧=) to make one. Drag the line between panes to resize them (double-click it to make them equal again); Tabs › Split View has the layouts (⌃⌥⌘1 / 2 / 3), Swap Panes (⌃⌥⌘S) and Next / Previous Pane (⌃⌥⌘→ / ←).
• Sleeping tabs: a page you have not used for 30 minutes (Library › Settings: 15 minutes to 2 hours, or never) closes to free its memory, about 80 MB each, and wakes where you left it, scroll position, form values and Back included, when you go back; its tab fades meanwhile. Pages on screen, playing sound, in a call or sharing the screen stay awake, and so do Favorites (a switch) and any site you keep awake (Control Center, a tab's menu). Sleep Tab and Sleep Other Tabs free memory at once; Tabs › Task Manager shows what each awake page uses.
• Back where you were after a restart or a crash: each tab's Back list and scroll position are saved every few seconds, so a page opens scrolled where you left it (not for profiles that forget their site data). The sidebar itself is saved within half a second of every change, and Library › Settings keeps hourly copies.
• Little Window: links from other apps (and ⌥⌘N) open in a small window; "Open in Space" moves the page into the sidebar. A Little Window left alone for 6 hours goes to the Archive.
• Shortcut from any app (Library › Settings, off until you pick keys such as ⌥Space): brings up the Command Bar, or a Little Window, without switching to Bow first. If another app holds the keys, Settings says so.
• bow:// addresses and Raycast: other apps can open an address in a Space, switch Spaces, search the open tabs or open the Command Bar with text (open "bow://open?url=github.com&space=Work"). integrations/raycast has three Raycast script commands built on them (Open in Bow, Switch Bow Space, Search Bow Tabs); Alfred and Shortcuts can use the same addresses.
• Boosts: change a site's colors (shift them, or invert for a dark look) and font, Zap elements away, and add your own CSS and JavaScript (only once switched on). Turn a Boost off or reset it any time; Library › Boosts. Share one as a .bowboost file (Export…, Import…; imported JavaScript arrives switched off), and a "JS" badge in the toolbar says when a JavaScript Boost runs on the page.
• Developer Mode per site (on by itself for localhost): a striped toolbar with the full address, Console, Network and Inspect buttons, a reload menu with Hard Reload, and the tab outlined in yellow.
• Show full URLs (Library › Settings, View › Toggle Full URLs, or the Command Bar): the toolbar shows the whole address instead of site and path, like Arc's preference of the same name.
• Notes and Easels: rich-text notes and boards (text, drawing, pictures, captures) that sit in the sidebar like tabs (File › New Note / New Easel). A capture placed on an easel is live, like Arc's: it is taken again from its page (same size, scroll and region) when the easel opens, or when you click its Live badge.
• Passwords: after you sign in on a site, Bow asks "Save password for example.com?" (Save, Not now, Never for this site; Update when the password changed). Click or Tab into the sign-in field next time and a small list under it offers your saved logins; pick one and the email and password are filled (nothing is filled before you pick). Bow also remembers what you type into forms (emails, names, phone numbers, addresses, never card numbers, codes or searches) and offers it again on any site. Library › Passwords lists everything per profile; Show, Copy and Edit ask for Touch ID or your Mac's password. Importing from Arc, Chrome, Dia, Brave, Edge, Vivaldi, Opera or Chromium brings their saved passwords straight over (macOS asks once to let Bow read them); Safari's Passwords app and Firefox come by their exported CSV file (Library › Passwords, File › Import From Browser, or the first start). Passwords are encrypted with a key in your Keychain, stay on this Mac and are never in backups or sync. Private windows never save anything.
• Ad and tracker blocking with EasyList and EasyPrivacy (off until you turn it on in Library › Settings), allowed per site in the Control Center.
• Privacy report (Library › Privacy): how many trackers the blocker stopped in the last 7 days, a bar per day, and the sites and tracker hosts with the most blocks, like Safari's report. Counts only, kept 30 days, never from private windows.
• HTTPS-Only Mode (Library › Privacy): pages asked for over http load over https. A site without a secure version says so in the sidebar, with "Open with HTTP" (allowed until Bow quits); a typed https:// address is never taken down to http, and local names and IP addresses stay as they are. Little Windows and Peek show the browser's error page instead of the offer.
• Forget site data on quit, per profile (Space menu › Profile, or Library › Privacy): cookies, sign-ins and what sites store are cleared every time Bow quits, and again at the next start should it crash. Extensions keep their own data; you sign in again each time.
• Air Traffic Control: rules such as "address contains github.com → Work" or "link comes from Slack → Work" send links from other apps to a Space (Library › Settings, which lists your running apps). The sender is the app in front when the link arrives, read with macOS's own lsappinfo (no permission needed). Test a link there shows where a pasted link would open, from any app or a chosen one.
• Permission prompts: a site that wants your camera, microphone, location, notifications or clipboard asks first ("meet.google.com wants to use your camera and microphone", Block / Allow). The answer is remembered per profile and site; the site controls list it with a Reset. Private windows ask every time and remember nothing. Links to apps (mailto:, zoommtg:, steam:, …) ask every time and name the app macOS would open. Sharing your screen (Meet, Zoom, Slack in the browser) opens macOS's own sharing picker, where you choose what to share.
• The Control Center (Arc's site controls): Share, Boost, Screenshot, Capture (drag over part of the page), the profile's extensions, per-site settings, and more behind "…" (Translate Page, zoom, clear site data, developer tools). Find in page, downloads, Print (⌘P), spelling suggestions, a right-click menu in pages, and automatic picture-in-picture when you leave a tab playing a video: the tab's own page floats in a small window of ours, the video filling it, with its title, Back to Tab, close, play / pause, mute and the progress showing while the pointer is over it. A video in an embedded player (a YouTube or Vimeo player inside an article) floats the same way.

Extensions

• Chrome extensions per profile, like Arc: imported from Arc, added from the Chrome Web Store (open an extension's page and click Add Extension in the toolbar), or loaded from a folder (Library › Extensions › Load Unpacked…). Web Store extensions update by themselves (a minute after start, then every 5 hours, or Check for Updates). Each download is checked like Chrome checks it: signed by the extension's own key, before anything is unpacked. Content scripts and Manifest V3 service workers run in Electron itself; the electron-chrome-extensions library (MIT) adds the browser parts: the puzzle button in the toolbar opens an extension's popup, chrome.tabs knows the selected tab, extensions can open tabs, and their items appear in the page's right-click menu.
• Password managers' desktop links work (native messaging, e.g. Apple Passwords, 1Password, Bitwarden): hosts registered for Chrome are found directly, and those registered only for Arc, Brave, Edge, Vivaldi or Chromium are linked in at startup.
• Some extensions need Chrome features Electron does not have (side panels, tab capture); those load but only partly work.

Library (⇧⌘L): like Arc's, it takes the sidebar column (which widens for it) with a rail of sections: Media (screenshots and captures), Downloads, Spaces, Boosts, Archived Tabs (search, filter by reason, click to restore), History, Extensions and Settings (search engine: Google, DuckDuckGo, Bing, Brave Search or Kagi; ad blocking, app icon, import from Arc, Chrome, Brave, Edge, Vivaldi, Firefox or Safari). The page stays usable beside it; ← or Esc closes it.

Also: a short welcome tour on the first start, Handoff of the page you are reading to your other Apple devices, and alternate app icons for the Dock.

Auto-archive, like Arc

A Today tab you have not used for 12 hours (the default; 1 hour to 30 days, or never) moves to the Archive. Pinned tabs and Favorites never do. A tab counts as used while it is on screen, playing sound or in Picture-in-Picture. These timings match what we measured on a real Arc install. The sweep runs every 5 minutes, the tab on screen is refreshed every minute, time while the app is closed does not count, and the Archive keeps the newest 250 tabs. The evidence is in docs/research/arc-findings.md.

Better than Arc, without surprises: a Today tab shows the minutes left in its last hour, a tab marked Never Archive (its menu) stays even through Clear, each Space can have its own timing (right-click the Space), the sidebar offers Undo for a few seconds after the sweep or Clear, and ⇧⌘T reopens only tabs you closed yourself.

Keyboard shortcuts

Same keys as Arc. ⌘T new tab, ⌘N new window, ⇧⌘W close window, ⌘L edit address, ⌘W close, ⇧⌘T reopen, ⌘D pin/unpin, ⇧⌘C copy URL (⌥⇧⌘C as Markdown), ⌘S sidebar, ⌘[ / ⌘] back/forward, ⌘R reload, ⌥⌘↑ / ⌥⌘↓ previous/next tab, ⌘1–⌘9 tab N, ⌃Tab / ⌃⇧Tab recent tabs, ⌃⌘N new note, ⌥⌘← / ⌥⌘→ previous/next Space, ⌃1–⌃9 Space N, ⇧⌘K clear Today, ⌃⇧= split view, ⌃⇧- close pane, ⌘O open Peek as tab, ⌥⌘N Little Window, ⌘F find, ⇧⌘L Library, ⌘+ / ⌘- / ⌘0 zoom, ⌥⌘I developer tools. Library › Shortcuts changes them: click a command's keys and press new ones (keys another command or macOS uses are refused, saying which), × removes them, Reset All brings back every default. Beyond Arc: ⌘, Settings, ⇧⌘S Save Page As, ⇧⌘A Search Tabs (every tab in every Space, with where it lives), ⌘/ Keyboard Shortcuts, a sheet of every shortcut read from the menu itself, so it is always right.

Tab power tools. ⌘-click and ⇧-click pick several tabs; right-click one of them to close, move, pin or split them all (closing comes with Undo). Typing an address you already have open switches to that tab (the sidebar offers "Open Another"), and Tabs › Close Duplicate Tabs tidies up the copies that piled up.

Everyday basics. Zoom is remembered per site (per host, like Chrome) and comes back the next time the page opens; private windows remember nothing. Library › Settings picks the folder downloads go to, or asks where to save each one. Search keywords you add there ("yt" → a search address with %s) let you type "yt cats" in the address field or the Command Bar to search that site directly. File › Export as PDF… saves the page as a PDF.

How the code is organized

Folder	Runs in	What it holds
src/main	Electron's main process	State rules (pure functions), main windows, web views, menus, overlay panels, Peek, Little Windows, import from Arc
src/renderer	The sidebar page	The sidebar and toolbar, drawn from the state
src/overlay	The overlay page	Command Bar, Library, site controls, Find, the Peek frame
src/little	A Little Window's bar	Address, Copy Link, Open in Space
src/preload	Before each of our pages loads	The only bridges between our pages and the app
src/shared	Both	Data types, settings with their sources, message names
tests	Vitest	Rules for state, Spaces, splits, auto-archive, ranking, history, the Arc importers
e2e	Playwright + Electron	The real app driven end to end, extensions (with a synthetic test extension), the permission check, the packaged app, the README screenshots
build, tools	—	The app icon (our own drawing) and Info.plist additions; scripts that draw the icon and package the app
docs	—	Screenshots, arc-teardown.html (Arc's 54 features and which are built here), research/ (findings, Arc's data model, RE setup)

Three ideas keep it simple:

1. Pure state functions. state.ts, spaces.ts, split.ts, tree.ts and autoArchive.ts take data in and return a changed copy. No Electron, no clock.
2. One way to change state. applyChange() in browserCore.ts saves, updates the web views and redraws.
3. Reconcile, then render. syncTabViews() makes the web views match the state; each page redraws from the newest state.

Security

• Web pages run sandboxed. Their only scripts of ours run in an isolated world, so page scripts see nothing new: one that gives Google's sign-in pages Electron's own user agent (Google refuses Bow's Chrome one there), and in profiles (never private windows) the helper that notices sign-in fields and fills a login you picked. The app trusts nothing that helper says about where it is: the site comes from the page's own frame, and a login is only ever sent to the page it was picked for. In a profile that has extensions, the extension library's preload runs too. Our own pages only accept their own messages, and every message field is checked.
• Saved passwords are encrypted with a key in the macOS Keychain (one file per profile); showing, copying or editing one asks for Touch ID or your Mac's password.
• Websites get nothing they were not allowed: camera, microphone, location, notifications and clipboard reading need the user's Allow (remembered per profile and site), screen sharing goes through macOS's sharing picker, everything else is refused, except full screen and clipboard writes. Our own pages are refused without asking. e2e/permission-check.mjs proves it.
• Our pages cannot navigate away or open windows, and only load their own scripts. The only exception: each window's sidebar opens the card's two corner pages the app asks it for, so they share its process.
• Import from Arc only reads Arc's files (its history database through a temporary copy) and never changes them.

Contributing

Bug reports, ideas and pull requests are welcome: start with CONTRIBUTING.md. Please report security problems privately (SECURITY.md). Everyone taking part follows the Code of Conduct.

License

Bow is released under the MIT License. It is built on Electron and electron-chrome-extensions (both MIT); ad blocking uses the EasyList and EasyPrivacy lists, downloaded when you turn it on.