Not Just Another Contact Tracing!

This Local Contact Tracing (LCT) app is basically a digital version of the “visitor check in book” that we strongly recommend as a complement to NHS and national digital and bluetooth track and trace. Until we all get vaccinated against covid 19, we hope this LCT app will help you keep track of your gatherings during the festive season. (Do not forget to wear masks and keep the social distance!) This LCT app is privacy preserving; all travel history is kept in local devices and for a maximum of 14 days only. It allows a visitor to contact the host and all other visitors attended the same event instantly at the press of a button, should this visitor have tested positive for covid afterwards.

There are two roles in this "local contact tracing", Room and Visitor. Room is the host, and there are many visitors visiting the host. For the human actors, Room has a name such as "Fikka Nursing Home", "Starbuck 5th St", "Maths 101 Workshop", "Xmas dinner at Mum's" etc. and Visitor can be represented by some acronym such as "MC", a first name such as "Michael", or some student ID, eg. "1045246D" etc.  Different visitors may have the same name, e.g. there could be more than one Michael in "Starbuck 5th St". But the Room name must be unique and have a one-to-one correspondence to the physical location or meet-up.

Under normal circumstance, we expect a Room, and similarly a Visitor, to record the history of visits using their own device (e.g. phone, notepad, laptop, PC) that has a web browser. However, since the connectionID we use is a unique combination of (nick)name+deviceID and the web browser used, a single device can be used to manage the visiting records of many combinations of Rooms and Visitors. But to prevent errors, we strongly recommend that a single device is used to keep visit records for ONE Room/Visitor only. Furthermore, as the communicationID is made up of (nick)name+deviceID, we can have e.g. two Michaels visiting the same Room. While the Room will see two "Michael" in the check in list, the alert and warning setting can distinguish the two Michaels.

Features Advantages over Bluetooth
Like a WhatsApp “check-in book” Focus is on the groups vs. individuals
Track high transmission risk groups Not Bluetooth; no smart phone needed
Minimum administration Low false negative by design
Messaging over internet Local management information and control
Covid-safe register Decentralised - avoids data overload and data loss
No personal information - by clearing cache
It scales exponentially with very little overhead

The QR codes below will take you to a "Room" page or a "Visitor" page. Use “Room” page if you are hosting an event and tell your visitors to go to the “Visitor” page to check in to your event. You should also tell your visitors the Room name you have chosen for your event so that they can check in into the right Room. That is all you need to do, leave the rests to the app! To make sure you are using the latest build of the software, press Shift/F5 to do a hard refresh.

Please follow instructions on Room Guide, or on Visitor Guide as appropriate.  Enjoy and be safe!  We really appreciate your feedback; tell us how we can improve this LCT app to help keep everyone safer, and how we can make this tool complement the national bluetooth track and trace of individuals.  See LCT Data Policy for more technical details.  For further queries and feedback please contact

Three youtube demo videos for:
(i) On Boarding -
(ii) Check In -
(iii) Alert & warning -

1) Room (or Host) (Click the following URL, or scan the QR code to go to Room web app"

Stable version:

Beta version:

2) Visitor (Click the following URL, or scan the QR code to go to LCT Visitor web app"

Stable version:

Beta version:

Go back to Room, Visitor or Data Policy. If you have any feedback, please email