Putting it on the counter phone.

Step 1

Open the download link on the counter phone

Tap the link in whatever browser the phone uses. The file is about 27.7 MB, so on a slow connection give it a minute. When it finishes, the browser will ask whether you want to open it — say yes.

If nothing seems to happen, look in the phone's Downloads folder and tap the file called laarialert-latest.apk there.

Step 2

Allow your browser to install apps

Android will stop you with something like “For your security, your phone is not allowed to install unknown apps from this source”. This is normal and it is not about LaariAlert specifically — Android asks this the first time any app is installed from outside an app store.

Tap Settings on that prompt, turn on Allow from this source, then press back. The install carries on where it left off.

Step 3

The Play Protect warning — what it actually means

Google Play Protect may show a warning: it does not recognise the app, and it will offer to cancel the install. Read that screen carefully rather than rushing past it, because you should be suspicious of files from strangers.

Here is what it is telling you, plainly:

• The app is unknown to Google, not unsigned. LaariAlert carries its own signing certificate. Google has not reviewed it because it was never submitted to the Play Store — that is the whole of the warning.
• Android checks the signature from then on. Once installed, the phone will refuse any future update that is not signed with the same certificate. That is what stops someone slipping a different app onto the counter phone later.
• Updates are checked before they install. Each one is downloaded over an encrypted connection and matched against a published fingerprint first.

To continue, choose the option to install anyway — the exact wording varies by phone, and on some it is behind More details.

Step 4

Give it notification access

Open LaariAlert. It walks you through what it reads before it asks for anything, then sends you to Android's Notification access screen. Find LaariAlert in that list and switch it on. Android will ask you to confirm.

This is the permission the whole app rests on: it is how the bank's own notification reaches LaariAlert. It is also the one worth understanding before you grant it — what it can see spells out exactly which apps get read and which never are.

Step 5

Let it survive the battery manager

This is the step people skip, and it is the reason apps like this go quiet after a few days. Phones aggressively shut down background apps to save battery. If that happens to LaariAlert, payments arrive with no chime and nobody notices until a customer is waiting.

The app has a guided walkthrough for this — follow it. There are two parts:

• Battery optimisation. LaariAlert asks to be left alone by the battery manager. Allow it.
• Autostart. On many phones sold here — Xiaomi, Oppo, vivo, Realme, Samsung — there is a separate autostart or background permission buried in the manufacturer's own settings. The walkthrough points you at it for your phone.

Keeping the phone plugged in at the counter helps here too, on top of the obvious reason.

Step 6

Tick your bank, then test it with one rufiyaa

In which apps to watch, tick the banking app your shop actually receives money in. Nothing that is not ticked is ever read.

Then prove it works before you rely on it: send one rufiyaa to the shop account from another phone and listen for the chime. If you hear the amount spoken, the counter phone is ready.