Are your sites up? Look at the menu bar.

If you turn that on, yes. Background watching is a checkbox in the widget’s config (right-click → the gear) and it ships OFF. With it on, the checks run in the app’s native layer — a Rust thread, not a timer in the web view — so they happen with the panel closed and the tab never opened. What it does need is Toolbox running, which it is, because it lives in your menu bar. If you quit the app or the machine is asleep, nothing gets checked; that is the job of a monitor hosted somewhere else.

Because hitting someone else’s site every minute from a menu-bar app is bad manners, and that includes hitting it on behalf of a user who never asked. The widget was built without automatic polling for exactly that reason, and the background check did not reverse the decision — it made it yours to make. So you turn it on, the interval has a floor of 5 minutes and a ceiling of one day, and until then the only requests are the ones you can see: one per site when you open the widget, plus the ones you ask for with Re-check.

Whatever you set between 5 minutes and 24 hours; new setups start at 10. The floor is not arbitrary — 5 minutes is where the free hosted monitors start too, and it keeps watching ten sites at roughly two requests a minute in total. The native layer clamps the value on its own, so a number outside the range gets pulled to the nearest edge rather than silently disabling the watch.

No. It notifies on the transition, not on every failed check: a site down for three hours sends one notification. The first check of a site never notifies either, because turning the watch on with two already-broken sites would otherwise fire two notifications at once about something you already knew. And coming back up is a separate toggle — going down always notifies, the recovery notice is the part you can switch off.

Green is a 2xx. Amber means the server answered but not with a 2xx — a 403, a 500, a 301 chain that ended somewhere unhappy — which is a different problem from silence. Red means no HTTP response at all: DNS failure, refused connection, timeout. Each row shows the status code and how many milliseconds the response took, plus how long ago it was checked, so “green, 2400 ms” tells you something a plain green dot would hide.

For the notification, yes — and deliberately. You are watching one specific URL, so if it starts answering 404, something broke. The panel still shows it amber, because in the panel the distinction between “answered wrong” and “did not answer” is worth keeping; the notification only has one bit to spend, and it spends it on “this is not serving what it used to”.

Yes. A URL you type is a URL it checks, private addresses included — type the scheme and port for those (http://localhost:3000), since a bare host gets https:// added for you. What is blocked is a different thing: a public site that 30x-redirects the request into loopback or your LAN, which is how a URL check gets turned into a probe of services that trust the local network. The gate looks at where the request started, so your own dev server keeps working.

Not today. That is a real gap and worth saying plainly rather than implying otherwise: the check reads the HTTP response, and reading the certificate’s expiry date needs a separate TLS handshake and parsing the certificate by hand, which is its own piece of work and is not built yet. A site with an expired certificate will usually show up red anyway — but as a failed request, without a date and without warning you in advance.

One GET per site per round, whose body is deliberately never read: the widget takes the status code and the timing and drops the connection, so nothing is downloaded. It follows at most 5 redirects and gives up at 15 seconds. It is still a real request, so it appears in your access logs and in any server-side counter — but no browser runs, so no page JavaScript and no client-side analytics tag fires.

Yes, in two places. The widget declares that it posts OS notifications, so it shows up in the per-widget mute list in Settings, and the global notifications switch covers it too. Either one silences it while the checks keep running and the panel keeps showing the colors — which is the point of separating them.

The panel says “Watching every 10 min” above the list whenever it is. That line is not decoration: in a monitor, the only thing you cannot afford to confuse is “it didn’t warn me because everything is fine” with “it didn’t warn me because it’s off”, and someone who enabled it a week ago has no other way to tell.

Yes. Webstarted Toolbox is a free beta, needs no account, and Website Monitor comes built into the app — there is nothing to install and nothing to enable, beyond the background watch if you want it. It is desktop only: macOS menu bar and Windows tray.