Privacy policy

Last updated 12 October 2026. Applies to the hot sia! app (Android, iOS, web) and this website.

In short

• hot sia! has no accounts. We do not ask for your name, phone number, email or address.
• The blocks you follow and your settings are stored only on your phone.
• We do not sell, rent or share personal data, because we do not collect it.

Who we are

hot sia! is made by a small team for the DAISI Challenge Singapore 2026. Contact us at hotsia@cervonwong.com.

What the app stores on your phone

The HDB blocks you follow (up to 3), whether you turned on the setting for people aged 65 or older or with a long-term illness, and your language choice. These stay on your phone. We never receive them. To delete them, remove the blocks in the app or uninstall the app.

What the app downloads

To show tonight's levels, the app downloads one public file with the heat level for every HDB block. The request contains nothing about you or the blocks you follow; the app looks up your blocks on the phone. Like any web server, the server that hosts this file can see your device's IP address and the time of the request. We do not use this to identify anyone.

Alerts (when switched on)

If a version of the app offers alerts and you allow notifications, your phone subscribes to an alert topic for the planning area of each block you follow (for example, Bedok). This uses Firebase Cloud Messaging, a Google service, which gives your phone a device token. We do not store device tokens and cannot link a topic to a person. See Firebase privacy information.

Maps (when switched on)

If a version of the app shows a map, the map comes from Google Maps. Google receives the map area you look at and your device's IP address. See the Google Privacy Policy.

Staff sign-in

A later version will let invited staff of care organisations sign in with role accounts (Firebase Authentication). Residents never need to sign in. This section will be updated before staff sign-in is released.

This website

This site uses no cookies, no analytics and no advertising. Fonts are served from this site, not from a third party. Our hosting provider processes your IP address to deliver the pages and to protect the site.

Children

hot sia! is meant for adults, including older adults and caregivers. It is not directed at children.

Singapore law

We follow the Personal Data Protection Act 2012. Because we do not collect personal data through the app, there is usually nothing for us to access, correct or delete. If you think we hold data about you, write to hotsia@cervonwong.com and we will reply within 30 days.

Changes

If we change how the app handles information, we will update this page and the date at the top before the change is released.