How do I block websites on Arc browser on a Mac?

The reliable way is to block at the operating-system level with the free Focuh Mac app. You start a focus session, and it blocks your chosen sites across Arc, Safari, Chrome, and Firefox at the same time using macOS Accessibility APIs. Because the block lives in the OS rather than inside Arc, switching to another browser doesn't bypass it. You can also install a Chrome extension in Arc since Arc is Chromium-based, but that only covers Arc.

Does Arc browser support Chrome extensions for blocking?

Yes. Arc is Chromium-based, so it can run in-browser blockers. The catch is the same as in Chrome: an extension installed in Arc only blocks Arc. The moment you open Safari or a native app, the block is gone. An extension is fine if Arc is the only place you get distracted; for blocking that survives switching browsers, you need OS-level blocking instead.

Why can't a browser extension fully block sites in Arc?

A browser extension only controls the browser it's installed in. Install a blocker in Arc and it blocks Arc — not Safari, not Chrome, not Firefox, and not native desktop apps. The most common bypass isn't disabling the extension; it's simply opening the same site in a different browser. Since most Macs have two or three browsers installed, a single-browser block has an obvious escape hatch that OS-level blocking closes.

Is there a free way to block websites on Arc?

Yes. The Focuh Mac app is free and blocks sites system-wide, covering Arc along with every other browser during a focus session. Mac and the web app use a free Clerk account so Today stays in sync. An Arc-only extension can work if you never leave Arc, but switching to Safari or Chrome bypasses it — OS-level blocking is the setup that holds.

Will blocking sites at the OS level break Arc's features?

No. The Focuh Mac app blocks specific domains during a focus session by intercepting navigation at the system level; it doesn't modify Arc itself or touch its Spaces, Boosts, or split view. Arc works exactly as normal — the only difference is that blocked sites won't load while a session is running. When the session ends, those sites are reachable again with no leftover changes to the browser.

Can I block native Mac apps too, not just Arc?

Yes. Because the Focuh Mac app blocks at the operating-system level, a focus session can block native apps like Messages, Slack, or a desktop YouTube app alongside websites in Arc and other browsers. A browser extension can never do this, since it has no reach outside the browser. If your distractions include both Arc tabs and desktop apps, OS-level blocking is the only thing that covers both at once.

How hard is it to bypass the Mac app's blocking?

Much harder than a browser extension. An extension can be turned off from the browser's extensions page in two clicks. The Focuh Mac app blocks through macOS Accessibility APIs and doesn't sit in Arc's settings, so disabling it mid-session takes deliberate effort rather than a quick toggle. That added friction is the point: it gives the urge time to pass instead of handing you an instant off switch.

Should I use the extension or the Mac app for Arc?

The Mac app. Download Focuh for Mac to block Arc plus every other browser and native apps. Launch the web app for Today with the same Clerk account. An Arc extension only covers Arc tabs.

Arc browserMacwebsite blockersystem-level blockingfocus

How to Block Websites on Arc Browser (Mac)

June 22, 20269 min readFocuh

To block websites on Arc browser on a Mac reliably, use the free Focuh Mac app and block at the operating-system level — a focus session covers Arc, Safari, Chrome, and Firefox at once, so switching browsers doesn't get you around it. An in-browser blocker only covers Arc. Here's how OS-level blocking works and when a single-browser block is enough.

Can you block websites in Arc with an extension?

Yes — Arc is Chromium-based, so it can run in-browser blockers. Installing one is straightforward. The problem isn't installing it — it's the ceiling. An extension installed in Arc blocks Arc and nothing else. Open Safari, open Chrome, launch a native app, and the block is gone. On a typical Mac with two or three browsers installed, that's not a hypothetical bypass; it's the first thing you'll do the moment Arc tells you no. So an Arc extension is genuinely useful if Arc is the only place you get pulled off task — and not enough if it isn't.

Why OS-level blocking is the reliable answer

The fix for the single-browser ceiling is to stop blocking at the browser and start blocking at the operating system. When a site is blocked at the OS level, it's blocked everywhere on the Mac at once — Arc, Safari, Chrome, Firefox, and native apps — because the block doesn't depend on any one browser cooperating.

The free Focuh desktop app for Mac does this with macOS Accessibility APIs. You start a focus session, and your chosen sites stop loading across every browser simultaneously. There's no per-browser setup and no gap to slip through by switching apps. For the full reasoning on why this matters, see system-level vs browser website blocking.

How to block websites on Arc with the Focuh Mac app

Download for Mac. Mac and the web app use a free Clerk account so Today stays in sync.
Grant the macOS Accessibility permission when prompted — this is what lets the app block across every browser, including Arc.
Add the sites you want blocked: youtube.com, reddit.com, x.com, or whatever pulls you off task.
Start a focus session and pick how long it should run.
Open Arc and try a blocked site — it won't load. Switch to Safari or Chrome and try the same site; it won't load there either. That's the difference OS-level blocking makes.

Arc keeps working exactly as normal otherwise — Spaces, Boosts, and split view are untouched. The only change is that blocked sites won't load while the session runs, and they're reachable again when it ends.

Arc extension vs Mac app: which should you use?

	In-browser extension	Focuh Mac app
Blocks Arc	Yes	Yes
Blocks Safari, Chrome, Firefox	No	Yes
Blocks native Mac apps	No	Yes
Setup time	Under a minute	A couple of minutes
Friction to bypass	Two clicks (extensions page)	Deliberate effort (OS-level)
Price	Free	Free

Read honestly, a single-browser block wins on speed and the Mac app wins on coverage. If Arc is your whole world, an in-browser blocker can be enough. If you'll switch browsers or open a desktop app to get around a block — which is what most people actually do — the Mac app is the one that holds. Download for Mac, then launch the web app for Today with the same account.

Blocking native apps, not just Arc tabs

One thing no Arc extension can do, regardless of how it's configured: block a native Mac app. If your distraction is the Messages app, Slack, or a desktop client rather than a website, a browser extension has no reach there. Because the Focuh Mac app blocks at the OS level, a single focus session can block native apps right alongside websites in Arc and other browsers. For the app-blocking side specifically, see how to block apps on Mac.

Why Arc users hit the browser-switch trap

Arc tends to attract people who like browsers — and people who like browsers usually keep more than one installed. Arc for everyday work, Safari for quick logins, maybe Chrome for a site that misbehaves. That's exactly the setup that defeats a single-browser block. You put a wall up in Arc, hit it, and your hand is already reaching for Safari before you've consciously decided to. The block didn't fail because it was weak; it failed because it only guarded one of three doors.

OS-level blocking closes all the doors at once. When the block lives in the operating system, it doesn't matter how many browsers you have or which one you open next — the site won't load in any of them while a session runs. For Arc users specifically, that's the difference between a block that's a mild speed bump and one that actually holds, because the multi-browser habit that usually wrecks blocking is the exact thing the Mac app is built to cover.

How hard is it to get around?

Worth being straight about: a browser extension in Arc can be disabled from the extensions page in two clicks, so it's easy to bypass on impulse. The Mac app is much harder. It blocks through Accessibility APIs and doesn't live in Arc's settings, so switching it off mid-session takes deliberate effort instead of a quick toggle. That friction is the feature — it buys the few seconds an urge needs to pass. If you want the strongest version of this on a Mac, see how to block websites permanently on Mac.

The bottom line

Arc can run in-browser blockers, so blocking Arc tabs is easy — but an extension only ever blocks Arc, and switching browsers undoes it. For blocking that actually holds, use the free Focuh Mac app to block at the operating-system level, where one focus session covers Arc, Safari, Chrome, Firefox, and native apps together. Download for Mac to block across every browser at once, or launch the web app for Today.