Flecha
Open-source Chromium browser for Mac with Arc-style Spaces, a dev command bar and MCP for coding agents
Flecha is a free, MIT-licensed Chromium 158 fork for macOS that rebuilds Arc's sidebar, Spaces, Peek, split view and Little Arc-style window from scratch. It adds developer tools such as a command bar with gh, npm and mdn shortcuts, environment switching, a responsive view and local dev servers in the sidebar. A built-in MCP server, off by default, lets coding agents like Claude Code and Cursor read and drive tabs. The project is at v0.1.x and describes itself as early software used daily by its author.
74% Arc feature parity (yes = 1, partial = ½).
Built-in AI
No AI
No built-in assistant or model; an MCP server lets external coding agents drive tabs and ships off, switched on in Settings > Developer.
flecha.devNot counted in Arc parity: some people want AI, some avoid it.
Bloat check
None found
No account, analytics or crash reports. Connects only to sites you visit, Sparkle update checks at flecha.dev and extension updates; no ads, wallet or upsells.
flecha.devAds, crypto, paid upsells, news feeds, default-on telemetry, required accounts.
Organization
| Feature | Flecha | Arc | Note |
|---|---|---|---|
| Vertical sidebarTabs live in a vertical sidebar that is the main tab UI and can be hidden. | ✓ | ✓ | Vertical sidebar is the main tab UI; Chromium's tab strip and toolbar are hidden. Toggle with ⌘S.github.com |
| SpacesSeveral workspaces per window, each with its own pinned and open tabs, switched by swipe or shortcut. | ✓ | ✓ | Own pinned tabs, folders and Today tabs per Space; switch with ⌃1-9, ⌥⌘←/→ or a two-finger swipe.flecha.dev |
| Profiles per Space (shareable)Each Space can use its own browser profile (separate cookies, logins, history), and one profile can be shared by several Spaces. | ◐ | ✓ | Opt-in own storage partition per Space (cookies/logins), not a profile; history, extensions shared.github.com |
| Global favoritesPinned icons at the top of the sidebar shared by every Space (Zen calls them Essentials). | ✓ | ✓ | Icons at the top of the sidebar, the same in every Space.flecha.dev |
| Pinned tabs & foldersPer-space pinned tabs that act like bookmarks, with nested folders. | ✓ | ✓ | Per-Space pinned tabs with folders; closing one unloads it and returns to its pinned URL.flecha.dev |
| Auto-archive tabsUnpinned tabs close automatically after a set time and stay recoverable in an archive. | ✓ | ✓ | Today tabs archive after 12 h by default (1 d, 7 d, 30 d or never); archive keeps 500 and is searchable.github.com |
| Space themesPer-space colour or gradient themes. | ✓ | ✓ | Each Space has its own colour and emoji; dark mode uses a deep tint of that hue. No gradients documented.flecha.dev |
Browsing
| Feature | Flecha | Arc | Note |
|---|---|---|---|
| Split ViewTwo or more tabs side by side in one window. | ◐ | ✓ | Two panes with a resizable divider; 3 to 4 panes is on the roadmap.github.com |
| Link previewOpen a link in an overlay without leaving the current page (Zen calls it Glance). | ✓ | ✓ | Automatic for new-tab links from pinned tabs and favorites; any link's right-click menu offers it too.github.com |
| Mini windowA small, chrome-less window for links opened from other apps or a quick search. | ✓ | ✓ | Flechinha window (⌥⌘N); links from other apps open there by default once Flecha is the default browser.flecha.dev |
| Command barA ⌘T palette that searches tabs, history, bookmarks and browser commands. | ✓ | ✓ | ⌘T/⌘L searches open tabs, history, archive and actions; adds gh, npm, mdn, caniuse, JWT decoding.flecha.dev |
| Link routingRules that send links from other apps to a chosen space or profile. | ◐ | ✓ | External links open in a Flechinha (toggle in Settings); no per-site routing rules documented.flecha.dev |
| Site customizationPer-site custom CSS/JS, or zapping elements off a page. | ✓ | ✓ | Per-site TypeScript and CSS edited on Flecha's Boosts page (⌥⌘B); no element zapping documented.flecha.dev |
| Auto picture-in-picturePlaying video pops out into picture-in-picture automatically when you switch tabs. | ◐ | ✓ | Stock Chromium auto-PiP on tab switch (sites opt in via Media Session) is unpatched; no Flecha PiP UI.chromium.googlesource.com |
Compatibility & migration
| Feature | Flecha | Arc | Note |
|---|---|---|---|
| Arc importImports Arc spaces, pinned tabs and folders. | ✓ | – | Reads Arc's sidebar file: Spaces, pinned tabs and folders, favorites, history. Colours, Boosts, cookies stay behind.github.com |
| Chrome extensionsInstalls extensions from the Chrome Web Store. | ✓ | ✓ | Installs from the Chrome Web Store; v0.1.2 added an extensions section to the sidebar.github.com |
| DRM (Widevine)Netflix, Disney+, Spotify web and other DRM video/audio play. Chromium forks need a Google Widevine licence. | ✕ | ✓ | No Widevine: enable_widevine defaults on only for Chrome-branded builds; Flecha's args never set it.github.com |
| PasskeysWebAuthn passkeys, Touch ID and the system/iCloud keychain. | ◐ | ✓ | No passkey-keychain entitlement (Chrome-branded builds only); security keys/phone, not iCloud Keychain.github.com |
| SyncSpaces, pinned tabs and settings sync across devices. | ✕ | ✓ | No account and no sync between computers; Chromium sync is off (no Google API keys).flecha.dev |
| Mobile appiPhone, iPad or Android app that shares spaces with desktop. | ✕ | ◐ | macOS only; the project's own comparison says it is not a fit if you need a phone app.flecha.dev |
Extras
| Feature | Flecha | Arc | Note |
|---|---|---|---|
| Built-in ad blockerAd and tracker blocking without installing an extension. | ✓ | ✓ | EasyList and EasyPrivacy via declarativeNetRequest, on by default; no per-site allowlist yet.github.com |
Extension support
Which extension formats and stores run, beyond the Chrome Web Store row above. Not counted in Arc parity.
| Feature | Flecha | Arc | Note |
|---|---|---|---|
| Manifest V2 extensionsThe older extension format Chrome removed in 2025. Needed for full uBlock Origin and other extensions that block requests. | ✕ | ✕ | Stock Chromium 158 disables MV2; none of Flecha's patches restore it, so uBlock Origin won't run.chromium.googlesource.com |
| Manifest V3 extensionsThe current extension format used by the Chrome Web Store (and supported by Firefox and Safari). | ✓ | ✓ | Stock Chromium 158 runs MV3; Flecha's own shell is an MV3 extension.chromium.googlesource.com |
| Firefox add-onsAdd-ons from addons.mozilla.org or .xpi files install and run. | ✕ | ✕ | Chromium only installs Chrome-format (.crx) extension downloads; Firefox .xpi add-ons don't install.chromium.googlesource.com |
| Safari extensionsSafari web extensions (the App Store extension apps Safari uses) install and run. | ✕ | ✕ | Safari web extensions ship as Safari app extensions; Chromium has no host for them.developer.apple.com |