How FocusJar Blocks Sites at the System Level on macOS

If you’ve ever tried a website blocker, you’ve probably noticed the loopholes. Open a different browser. Switch to incognito. Disable the extension. Use your phone. The list goes on.

Most blocking tools fail because they operate at the wrong level of the stack. FocusJar takes a fundamentally different approach - one that blocks sites across your entire Mac, not just inside a single browser.

Why Browser Extensions Fall Short

Browser extensions are the most common type of website blocker. They’re easy to install and configure. They’re also easy to defeat.

A browser extension runs inside the browser process. It can only see and control traffic within that single browser. This creates obvious problems:

• Multiple browsers: Block Twitter in Chrome? Open Safari. Most people have at least two browsers installed.
• Incognito mode: Most extensions don’t run in private browsing by default. One click to a private window and the block is gone.
• Easy removal: Right-click the extension icon, select “Remove.” Done. No confirmation, no consequences.
• No persistence: Reinstall the browser and the extension - along with all your block lists - is gone.

Extensions treat blocking as a suggestion. For someone who’s genuinely struggling with distraction, suggestions aren’t enough.

Why DNS-Based Blockers Have Gaps

DNS-based blockers (like Pi-hole or some parental control tools) work by intercepting domain name lookups. When your browser tries to resolve twitter.com, the DNS blocker returns an empty result or redirects to a block page.

This is better than a browser extension - it works across all browsers and apps. But it has limitations:

• Easy to bypass with alternate DNS: Changing your DNS server to 8.8.8.8 (Google) or 1.1.1.1 (Cloudflare) takes seconds and routes around the block entirely.
• VPNs defeat it: Any VPN connection bypasses local DNS resolution.
• No granular control: DNS blocking works at the domain level. You can’t block reddit.com/r/funny while allowing reddit.com/r/programming.
• Configuration overhead: Setting up and maintaining a DNS-level blocker requires technical knowledge most people don’t have.

How System-Level Blocking Works

FocusJar blocks at the network level on macOS, operating below the browser layer. Conceptually, here’s what happens:

1. You start a focus session and select which sites to block.
2. FocusJar installs network rules that intercept connections to those domains at the operating system level - before any browser or app can reach them.
3. Every application on your Mac is affected. Chrome, Safari, Firefox, Arc, Brave, Electron apps, curl from the terminal - it doesn’t matter. The connection is blocked before it leaves your machine.
4. The rules persist through restarts. Rebooting your Mac doesn’t clear the block. The session continues where it left off.

This approach eliminates the most common bypass strategies. There’s no “other browser” to switch to. There’s no incognito escape hatch. There’s no extension to uninstall.

What Happens When You Try to Visit a Blocked Site

When you navigate to a blocked site during a focus session, you see a block page instead of the site content. The page tells you:

• Which site was blocked
• How much time remains in your session
• The option to unlock early - for a fee

That last point is critical. FocusJar doesn’t just lock you out with no options. You always have a way back - but it costs the amount you chose when starting the session. $5, $25, $100. Whatever you decided when you were thinking clearly.

Surviving Restarts and Resistance

One of the most common strategies people use to defeat blockers is simply restarting their computer. “If I reboot, the block will reset.” With most browser extensions, that’s true.

With FocusJar, the blocking rules are managed by a system-level process that starts automatically on boot. Your session state is persisted to disk. When your Mac comes back up, the block is already active - before you can even open a browser.

This also means the block survives:

• Force-quitting the FocusJar app
• Logging out and back in
• Switching macOS user accounts
• Putting your Mac to sleep and waking it

The Unlock Fee Is the Product

Here’s the part that makes FocusJar different from every other blocker: the fee isn’t a bug, it’s the feature.

Pure lockout tools (like Cold Turkey or SelfControl) make it impossible to access blocked sites. Period. This sounds tough, but it creates its own problems. What if you genuinely need to check something? What if there’s an emergency? The rigidity creates anxiety, which can actually reduce focus.

FocusJar takes a different approach: you can always get through the block. But it costs money. Real money that you chose when you were in a rational state of mind.

This design leverages loss aversion - the well-documented cognitive bias where losing money hurts about twice as much as gaining the same amount feels good. You’re not locked out. You’re priced out. And that price is enough to make most people think twice, close the tab, and get back to work.

The result: you stay focused not because you’re forced to, but because breaking focus has a real, tangible cost. And most people - once they see that cost staring back at them - choose to stay on track.