Using DEV.B

Getting started

1. Choose your country. The app switches to its language.
2. Check the language. Change it if you prefer another one.
3. Allow access. Allow location (to show how far danger is) and notifications (so alerts reach you). Bluetooth lets the app work without internet.
4. Add your photo (optional). It stays on your phone, and you can skip this step.
5. Add your local emergency numbers under Emergency call on the home screen.

Report danger

1. Press the big red Report danger button.
2. Choose what you see: flood, landslide, fire, dam or building collapse.
3. Optionally add a photo and a short note (up to 100 characters). Don't write names or private details.
4. Press Send report. If no one is in range, your phone keeps the report and sends it when it can.

Only report what you can see yourself. False reports put people at risk and may get a phone blocked.

Confirm a report

When someone nearby reports danger, your phone shows "Possible danger: Do you see it?" with the type of danger and how far away it is.

• Tap the green Yes, I see it only if you can see it yourself. Your "yes" also passes the alert on to the people around you.
• Tap the grey No if you are close but see nothing.
• If you are too far away to know, it is fine not to answer.

When enough different people confirm, everyone nearby sees Be ready (amber), then Danger confirmed (red).

Emergency bag checklist

Pack these now and keep the bag near the door. You can tick them off in the app's Guide tab.

• Water for 3 days
• Food that keeps
• Medicine
• Papers in a plastic bag
• Torch and batteries
• Power bank
• Radio
• Whistle

Find a shelter

The Map tab shows shelters with distance and walking time. The shelters in the current test version are examples, not real places. Until real shelters are added for your area, learn your local evacuation points from your local authorities.

Emergency numbers

Emergency numbers differ by country, so you save your own. Open Emergency call, tap Add number, and enter a name (for example "Police") and the number. To call, tap the number, then tap Call to confirm. The extra tap prevents calling by accident.

Relay mode

A relay phone is a phone left plugged in with DEV.B open in a central place, such as a school, clinic, place of worship or market. It helps alerts reach across a spread-out village. Any phone can be a relay: keep it charged, keep the app open and keep Bluetooth on.

The Relay phone switch in Settings keeps DEV.B passing alerts on while your phone is in your pocket. It is on by default.

Battery saver

Turn on Battery saver in Settings to hide the map and turn off screen flashing during alarms. Alarms still sound and vibrate.

Frequently asked questions

Is DEV.B free?

Yes. There are no ads and nothing to buy.

Is it an official warning system?

No. It is a community tool: warnings come from people nearby. It complements official sirens and messages; it does not replace them. Always follow your local authorities.

Does it need internet?

No. Alerts travel phone to phone over Bluetooth. That only works if other people nearby have the app.

Does it work when my phone is locked?

Yes, as long as you don't close the app by swiping it away. On Android, a small permanent notification shows that DEV.B is passing alerts on. iPhones limit Bluetooth when locked, so iPhones find each other more slowly in the background. You can turn this off with Relay phone in Settings.

Will it call emergency services for me?

No. Save your local numbers in the app and call them yourself.

Why does it need my location?

To show how far a danger is and to tell whether a person confirming a report was close enough to see it. Only a rough area (about 200 m) is ever shared. See our privacy policy.

Who can see my photo?

Nobody. It stays on your phone, and you can delete it any time in Settings → My photo.

What if I confirm by mistake?

In the current test version you can't change your answer yet. One mistaken "yes" alone can't raise an alert, because several different people must confirm.