Limits

Posato adds deliberate friction; it is not a lock you cannot open.

• It does not resist a device administrator and can always be removed. Ending a session early is always possible.
• On macOS, blocking works only while Posato is running. Closing its window keeps it running in the menu bar, and after the one-time setup Posato opens quietly at login. If Posato quits, or after sleep, wake, or a network change, a pause you started yourself stops blocking until you resume it in Posato. Without the setup, starting or resuming needs administrator approval each time. A session received from your iPhone blocks on the Mac only after you resume it there; without the setup, that also needs administrator approval.
• On macOS, schedules start only on a Mac that finished the setup and only while Posato is running. If Posato opens, including at login, or the Mac wakes during a scheduled pause, the pause starts again on its own, usually within a minute, and still ends at its planned time; no password is asked. Quitting Posato stops new scheduled starts until it opens again; closing the window does not.
• On macOS, paused apps are quit while a session is active, including apps that were already open when it started, so unsaved work in them can be lost.
• On macOS, website blocking covers Safari and Google Chrome Stable for web traffic on ports 80 and 443 while they use the system proxy settings. Firefox, other browsers, in-app browsers, and apps that bypass the system proxy are not covered. Visiting a paused site by its IP address is not blocked, and iCloud Private Relay can bypass blocking without being detected. A session does not start blocking while a VPN or a manually configured proxy is active. Connections to servers on the Mac itself (localhost, 127.0.0.1, and ::1) keep working during a session. Pages already loaded, cached, or downloaded are not erased, and the pause page may occasionally not appear even though the site stays blocked.
• On macOS, Posato uses a background helper that requires administrator approval and may ask for Automation permission to show its pause page in the current tab.
• On iPhone, the system clears restrictions after a session ends and may keep them for a while past the end time. Restrictions from sessions shorter than 15 minutes clear only when Posato is open at the end or when you open it again.
• On iPhone, if Safari was already open, the first page it opens after a pause that blocks websites ends may stay blank. This appears to be how iOS behaves when the restriction is lifted, and Posato cannot avoid it. The next page you open loads.
• On Linux, website blocking maps each paused website and its www name to 0.0.0.0 and :: in /etc/hosts, so connections to it fail. There is no pause page. A browser that uses its own DNS over HTTPS, visiting a site by its IP address, or another name of the same site bypasses it.
• On Linux, Posato installs a system service once, with your password. While a pause runs, the service ends the paused apps you chose, so unsaved work in them can be lost. It clears the pause at its end time even when Posato is closed. Removing the package clears an active pause. An app whose desktop entry starts a script, an interpreter, or Flatpak cannot be paused.
• On Linux, schedules start only while Posato is running. Closing its window keeps it running with an icon in the status area, and Open Posato at login in About Posato starts it in the background when you log in. On a desktop whose status area does not show app icons, such as GNOME without the AppIndicator extension, there is no icon; Posato then stays in the background only while a pause runs or a schedule is on, and you open it again from the applications menu. Quitting Posato stops new scheduled starts.
• On Windows, website blocking stops connections to the addresses that a paused website's name resolves to. A site that shares addresses with other sites, such as one behind a large content network, can block those sites too, and a site that moves to new addresses can open until Posato sees them, within about a minute. A browser with its own DNS over HTTPS can reach addresses Posato has not seen, and a connection already open when the pause starts stays open. There is no pause page, and a VPN or a proxy bypasses it.
• On Windows, the installer sets up a system service with administrator approval. While a pause runs, the service ends the paused apps you chose, so unsaved work in them can be lost. It clears the pause at its end time even when Posato is closed, and uninstalling Posato clears an active pause. Microsoft Store apps and shortcuts that start a script or a command line cannot be paused. Posato pauses only the Windows account that installed it. The installer is not signed yet, so Windows SmartScreen warns before it runs; choose More info, then Run anyway. With Smart App Control on, Windows blocks the unsigned installer, and Posato cannot be installed until the packages are signed.
• On Windows, schedules start only while Posato is running. Closing its window keeps it running with an icon in the notification area, and Open Posato at login in About Posato starts it in the background when you log in. Quitting Posato stops new scheduled starts.
• On Android, website blocking runs as a local VPN that only answers name lookups. Another VPN cannot run at the same time, strict Private DNS and a browser with its own DNS over HTTPS bypass it, and lookups over TCP are not filtered. There is no pause page.
• On Android, a paused app is covered by a block screen; it can be visible for up to about a second before the screen appears. The launcher, Settings, the phone app, and Posato cannot be paused. Posato needs usage access, display over other apps, notifications, and exact alarms; without them, blocking or schedules may not run. From 1.6.1 it no longer needs to be excluded from battery optimization; the 1.6.0 APK from GitHub Releases still does.
• A website that opens briefly during a pause (release 1.6) follows each device's own clock and time zone, so devices in different time zones open it at different moments. When its window ends, new page loads are blocked, but a connection that is already open, or an address the browser or system remembered, can keep it working for a while on Linux, Android, and Windows; on macOS, Posato also closes the connections it carries for it. On iPhone and iPad the system decides when Posato's background extension runs: a window can open up to about a minute late, and if the system never runs the extension at the window's end, the website stays open until the extension next runs or you open Posato. Safari on iPhone and iPad shows the system's restricted page, which does not say when the website opens; Session in Posato does. A rule cleared on another device takes effect on an iPhone or iPad only when Posato opens there, and on Linux or Windows only while Posato runs; until then, or until the pause ends, the website keeps opening on its old rule.
• A device on an earlier version of Posato stops syncing once another device takes a break in a scheduled pause or sets or clears a rule for a website to open briefly. Update Posato on every device to keep them in sync.
• A break lasts 5, 10, or 15 minutes, and each scheduled pause allows one. It reaches your other devices only when they sync, so a device that has not synced keeps restricting until the break reaches it or ends. On iPhone and iPad with Posato closed, restrictions can return a few minutes after the break ends, because the system decides when Posato's background extension runs; when the system cannot schedule that return, Posato takes no break. On Android, Linux, and Windows, restrictions return within about a minute of the device next waking if it slept through the break's end.
• Schedule times follow each device's own clock. A schedule is at least 15 minutes long, and on iPhone it needs Screen Time access.
• A device on an earlier version of Posato stops syncing once another device runs Posato 1.3. Update Posato on every device to keep them in sync.
• Sync is best effort. Posato cannot promise when, or whether, a change reaches your other device, and it cannot wake a sleeping device.
• If every copy of the workspace key is lost, synchronized data cannot be recovered. Data already copied to another device cannot be erased remotely.
• Folder sync works through a folder that a service you already use keeps in sync, such as Dropbox, OneDrive, iCloud Drive, or Syncthing. Posato writes only encrypted files there, but it cannot control when, or whether, that service delivers them, and anyone who can delete files in the folder can stop your devices from syncing.
• A device joins a folder workspace with a one-time pairing code that is valid for 10 minutes, scanned as a QR code, opened as a link, or typed. Someone with the code or the link and access to the folder, or to its file history, can open the workspace, so share the link only with your own devices. There is no way to remove a single device: to stop sharing with one, remove the workspace and create a new one in another folder.
• In folder mode, each device keeps the workspace key in a file that only your user can read, not in the Keychain. On Android it is protected by the Android Keystore.
• On Android, the folder must be a local folder that another app keeps in sync, such as Syncthing; most cloud storage apps for Android do not keep a local folder in sync. From 1.6.1 you choose it in Android's folder picker, and Posato can access only that folder; after an update from 1.6.0, Posato asks you to choose it again. On iPhone, Posato syncs the folder when you open it.
• An exported .posato file holds pause set names, websites and their rules for opening briefly, the default set, and schedules, never app choices. Without a code, anyone who gets the file can read it. The nine-character code stops a casual reader, not someone who spends a lot of computing power on guessing. An import is a one-time copy, not sync, and imported schedules arrive switched off.
• A workspace syncs through iCloud or through one folder, never both, and there is no move between them: remove the iCloud workspace before choosing a folder.

Posato targets macOS 13 or later on Apple silicon and Intel Macs, iOS 18 or later, Ubuntu 24.04 or later, Android 13 or later, and Windows 11 on x64 and Arm; see the platform matrix for what was checked on each. See the privacy policy for what Posato keeps on your devices, in iCloud, and in a sync folder.