A distraction blocker you can't talk yourself out of.

No, and not as a matter of policy — as a matter of what exists. Cloister has no way to end a session: no button, no hidden setting, nothing to find in a settings pane, nothing to hold a modifier key for.

• Sessions are capped at 24 hours of your Mac being on or asleep.
• A shutdown pauses them after its first ten minutes.
• Start with five minutes rather than five hours while you get a feel for it.

A site on a running session’s list stays blocked until the session ends. The sites a session blocks are fixed when it starts, so editing a list afterwards changes the next session, not the one running.

Read the list before you press Start, and start short: a session can be as short as a minute, and none runs longer than 24 hours.

No. Breaks are set before Start, like the session’s length, and nothing about a session changes after Start.

• Two choices: a 5-minute break every 25 minutes, or 10 minutes every 50. Each needs room: 25 + 5 from a 35-minute session, 50 + 10 from 70 minutes.
• Breaks don’t make a session longer. They are inside its length, and a session never ends on a break.
• Schedules can have breaks too, at the same clock times each day they run. If a schedule starts late, after your Mac wakes, a break already due is skipped, not moved or shortened. The Shortcuts action starts sessions without them.

They are blocked again when the break ends, including tabs that were already open: Cloister closes their connections, so a reload or a click is blocked like any other. Safari with iCloud Private Relay needs the network filter on, as it does for blocking. What can keep working:

• A video that is already playing may play to its end. Nothing new loads.
• A browser with its own secure DNS, such as Chrome with secure DNS or Firefox with DNS over HTTPS, or a proxy or VPN, may keep a break’s tab working for a while, as long as the browser keeps that connection open. Anything new is blocked as it would be outside a break.
• If Cloister’s menu says another app manages this Mac’s firewall (a VPN’s kill switch can), tabs opened during a break may keep working: close them when it ends. The block itself works as always.

Two side effects:

• Other sites on the same servers are cut once too. At a break’s end, their connections are reset and can’t reopen for about 15 seconds: with YouTube on a list, that may include Gmail and Docs. Devices sharing the Mac’s connection, such as virtual machines, are cut the same way.
• During each break, Cloister looks up every site on your list, visited or not, with your Mac’s own DNS, so that it can close their connections. Your DNS provider sees those names. Nothing is sent to us.

Yes, and you should know how before you buy. What gets past it:

• Apps that connect their own way. An app that finds its servers by itself, or connects straight to an address, is not blocked.
• Safari with iCloud Private Relay switched on gets past the block until Cloister’s network filter is on. The filter blocks Safari too, once you allow it in System Settings and turn it on in Cloister: in Settings → Coverage, or from the menu if it says “Safari isn’t blocked”.
• Switching Cloister off during a break. Switched off in Login Items, which takes an admin password, it leaves the sites open until it is switched back on, and Cloister’s menu says the break is still open. Stopped another way, it leaves them open until the Mac restarts. Outside a break, the block stays either way.
• Recovery mode. Anyone who starts the Mac in it can remove the block, always.

Tested, and didn’t get past it:

• Encrypted DNS in Chrome and Firefox: still blocked. Tested 20 September 2026 on macOS 26: Chrome set to Cloudflare, Firefox at Increased or Max Protection.
• A VPN app: still blocked in Safari, Chrome and Firefox, switched on before a session or during one. Tested 12 October 2026.

The honest claim is that Cloister makes giving up deliberate and inconvenient, not impossible — which is the only thing a commitment device can truthfully promise, because the person being blocked is the person who asked.

On the Mac, not yet: Cloister for Mac blocks websites only. A site on your list will not load in your browsers, but apps still open as normal, so Cloister does not stop Slack, Steam or Mail from launching.

Blocking apps is planned for version 2. Cloister for iPhone and iPad does block apps (see the last question).

Cloister can open sessions on a repeating schedule — weekday mornings, every evening, whatever shape your work or study has.

• A schedule is not a softer session: once one opens, it holds like any other, which is the point.
• Editing tomorrow’s schedule is always allowed; editing the session running right now is not.

Yes. Cloister adds three actions to the Shortcuts app:

• Start a Session, which blocks a list for 15 minutes to 4 hours. It asks before it starts unless you switch that off in the action.
• Get Time Left.
• Find Block Lists, which hands a list to the next action.

Start a Session and Get Time Left also run from Spotlight. None of them can end a session or shorten one. For a different length, or a block that repeats, use the menu bar or a schedule.

Not for the Mac. You pay once, and what the money buys is a window of updates — a year, or the life of the product.

• When that window closes, nothing is taken away: the last version you received keeps working indefinitely, and no session is ever cut short because a card failed.
• For the versions that come after, you can buy another year at the price of a new licence, whenever you like.
• Nothing renews by itself and nothing is charged to a card you left with us, because we do not keep one.
• No account. After a one-time activation on each Mac the licence is checked offline, so Cloister works with the network off, and there is no account to create.

Cloister for iPhone and iPad is sold differently, through the App Store (see the last question).

Yes — within 30 days of buying, for any reason, by writing to us. And with the 14-day trial first, you never have to pay to find out whether an uncancellable block suits you.

A refund never ends a session that is running. For a purchase in the App Store, ask Apple.

From Paddle, our reseller, which handles the payment, the invoice and the tax — Paddle is the name on your card statement. Cloister itself, its licence and its support come from Vitalii Kizlov, the one-person business in Poland that makes it.

Buying for a company? Enter your VAT number at checkout. On iPhone and iPad, you buy Cloister Pro from Apple in the App Store.

One or two, depending on which you buy.

• Activated once per Mac. The first time you enter your licence on a Mac, Cloister activates it once over the internet: it sends your licence key, a one-way hash of the Mac’s hardware identifier and the Mac’s model name, and gets back a licence signed for that Mac.
• Then offline. After that it contacts us about the licence again only if you unlink that Mac, renew or press Refresh licence, and works with the network off.
• Moving to a new Mac takes a click: unlink the old one in Cloister’s settings, or, if the old Mac is gone, from the new one when Cloister lists your Macs.

The app, no: no analytics, no crash reporter, no telemetry. Your blocklists and schedules never leave your Mac, and blocking happens on the Mac itself.

The business keeps your email, and a hash and the model name of each Mac you activate, because that is what a licence needs, and Paddle holds the payment details. The privacy page lists all of it — and Little Snitch will show you the app’s side: one activation per Mac, then only the check for updates — plus unlinking, renewing or refreshing the licence, when you do them.

In Cloister’s Settings → General, press Uninstall Cloister…, which removes its background item and its network filter, then moves the app to the Trash.

• It won’t run while a session is going: it says when the session ends, and you try again then.
• macOS asks for Touch ID or a password to remove the filter.
• Your trial record stays, so a reinstall carries on from it, and so do your lists and settings.
• If you deleted Cloister in Finder instead, download it again, open it, and uninstall it from there.

For Cloister for Mac: a Mac with macOS 15 Sequoia or later, on Apple Silicon or Intel.

• A signed, notarized download straight from this site — not a Mac App Store app, and it can’t be: App Store apps aren’t allowed the system-wide access Cloister needs to block websites in Safari, Chrome and Firefox.
• One approval: you will be asked to approve a background item in System Settings the first time you open it.

The iPhone and iPad app is separate (see the next question), and there is no Windows or Android version.

Yes: Cloister for iPhone and iPad is on the App Store, for iOS and iPadOS 26 or later. Since version 1.2 it is optimized for iPhone Duo, on both displays, closed or open.

• A separate app and a separate purchase: free to download, with Cloister Pro as a yearly or monthly subscription or a one-time Lifetime purchase, billed and refunded by Apple.
• It blocks apps, app categories and websites through Apple’s Screen Time, on a schedule or when you start it.
• A Strict block has no way out inside the app, but iOS keeps ways out that no app can remove; turning off Cloister’s Screen Time access in Settings is one, and it ends its blocks.

The other answers here are about Cloister for Mac; section 14 of the Terms covers the iPhone and iPad app.