The Alarm Sender extension for Firefox: how to answer an alarm here, what
to check when one does not reach you, and what a browser cannot be asked
to do.
This deployment · last updated 30 October 2026
· All support
Answer alarms from the popup
This is the one thing that works differently here, so it is first.
Firefox cannot hold a notification open until you answer it,
and it has no Acknowledge button on notifications. The alert usually closes
by itself after a second or two, taking the clickable part with it.
So answer alarms from the toolbar popup. The newest unanswered alarm sits
at the top:
| Button | What it records |
|---|
| Acknowledge | You dealt with it. The sound stops and any escalation stops. |
| Silence | The sound stops and nothing is recorded. The alarm still counts as unanswered. |
The two are kept apart on purpose: making a noise stop is not the same as
dealing with what caused it. Clicking the notification itself still
acknowledges, if you catch it in time.
A notification closing on its own is not recorded as you dismissing
it. That distinction matters — a dismissal would tell the service a person
had seen the alarm, and stop it escalating to your other devices.
Nothing happens after installing it
It has to be paired first, and until it is, the toolbar popup shows a
pairing form and nothing else. In the console open Devices,
choose Add device, and type the code it gives you into the
popup. The popup then says Listening.
There is no sign-up in the extension and it never asks for a password.
An alarm arrived late
Firefox stops an idle extension's background page after about half a
minute, and the connection goes with it. A one-minute timer brings it back
and anything missed is delivered then, marked late in Activity —
so on Firefox an alarm can be up to about a minute behind.
Nothing is lost by this: receipts are kept until the service has them, even
across a restart. But if you need an alarm at the moment it is raised, a
phone or a desktop client is the right receiver and this is a second one.
Opening the popup wakes the extension immediately, which is also the
quickest way to make it reconnect if the status looks stale.
The alert appears but makes no sound
The popup says so when a chime fails, with the reason under the status line
— worth quoting to us word for word. Otherwise check the chime is not set
to silent in the console, and that neither this computer nor
Firefox is muted in the system mixer.
No notification appears at all
Notifications are an operating-system permission as well as a browser one.
If the system is muting notifications for Firefox, the alarm still arrives
and still shows in the popup — only the on-screen alert is missing. On
Firefox that is worth knowing, because the popup is where you answer it
anyway.
What a browser cannot do
These are not faults waiting to be fixed. They are what a browser is:
- it cannot wake a sleeping computer
- it cannot ring through Do Not Disturb
- it does not run when Firefox is closed
The popup warns you when this browser is the only receiver on your account,
and a second browser does not satisfy that warning — two weak receivers are
still not a strong one.
Why it asks for what it asks for
| Permission | What it is for |
|---|
| storage | This device's pairing, your chimes, recent alarms, and receipts not yet delivered. |
| notifications | The alert itself. |
| alarms | A one-minute tick that reconnects after Firefox has stopped the background page. |
| alarmsender.com | Pairing, your chimes, and the connection that carries alarms. |
It reads nothing from your browsing — no tabs, no history, no page content,
no cookies — and it has no access to any site other than
alarmsender.com. There is no content script. The add-on
declares that it collects no data, and
the privacy policy has the full account of what is
sent and why.
A trigger that does not ring
-
Press Ring beside the trigger in the console. If that
rings here, the trigger and the extension are both fine and the problem
is with whatever was supposed to call it.
-
Open the trigger URL in a tab. It is an ordinary GET, and the reply says
what happened.
-
Check Activity. An alarm there that reached no device is
a delivery problem; nothing there means the request never arrived.
Is it us or is it you
Both hosts answer a health check with no sign-in, so you can tell the
difference without waiting on us:
curl https://alarmsender.com/health
curl https://alrm.sh/health
If those answer and your alarms do not, the problem is in delivery or
configuration rather than the service being down — say so when you write
and it saves a round trip.
Writing to us
support@alarmsender.com. Four
things make an answer much quicker, and you will usually have them already:
- which device — phone, desktop app, Chrome, Firefox
- roughly when it happened, and your timezone
- what you expected and what happened instead
- whether the alarm shows in Activity in the console
That last one splits the problem in half. An alarm in Activity reached the
service and the question is about delivery; nothing in Activity means
whatever was meant to raise it never did.
Please do not send us a trigger URL. Anyone holding one can ring your
alarms, and it never expires. The trigger's name is enough.
Alarm Sender is operated by Single Breath LLC.