Reliable mobile Bluetooth

Herald provides reliable Bluetooth communication and range finding across a wide range of mobile devices, allowing Contact Tracing and other applications to have regular and accurate information to make them highly effective.

Wide phone support
Wide phone support

97.5% of phones worldwide can use the Herald Protocol

Easy to integrate
Easy to integrate

Provide a few callbacks to the Herald API and integrate Herald to your app in minutes using your own payload


Does not restrict how people can use it, for contact tracing or any reliable Bluetooth communication

Measuring Bluetooth efficacy

Read an overview of how efficacy for contact tracing can be assessed

Learn how Herald is used for custom Bluetooth mobile apps

Learn how to create your own mobile app using Herald

Herald solves risk estimation problems

Herald estimation benefits


Detect nearby phones

100% detection of phones in the foreground and background across iOS and Android devices. Herald supports) 100% of the phones in the UK that support advertising, as well as the 35% of Android phones (~14% of all phones overall) that cannot act as ‘advertisers’ and so remain unseen by advertising-only based protocols.

Provide regular distance readings

Herald performs distance estimations every few seconds, with higher frequency on modern phones. This allows for a more accurate data and risk picture over time. Maximum frequency can be configured to optimise battery use. At ~4s per reading battery use is 6-11% over 8 hours), depending on the age of the phone and its battery capacity.

Interoperate internationally

By providing a common packet header we allow for international interoperability amongst all contact tracing applications, whether designed for centralised or decentralised contact matching and risk scoring.

Blog Highlights

Raw RSSI data released
Raw RSSI data released
The Herald Project team are pleased to announce the publication of our first dataset from our Edison distance calibration robot. This robot allows two phones to be placed at a precise distance in a controlled setting and moved distance over time.
Version 1.1.0 released
New guides added to website
New guides added to website
We’ve been busy getting ready for the upcoming V1.1 release. For this release we’ve dramatically changed our documentation on this website.


A lot of work has gone in to mobile app based contact tracing protocol research, design, testing and collaboration worldwide. We'd like to thank all of those in VMware Pivotal Labs and elsewhere worldwide that have assisted with various national and state governments to use mobile contact tracing to help save lives. ❤️


All Herald works are Copyright 2020 Herald Authors.

The code for Herald (Android, iOS, Analysis Scripts, Calibration tool) are Apache-2.0 licensed. The documentation for Herald, including this website, are under the Creative Commons Attribution 4.0 International Public License.

See LICENSE.txt and NOTICE.txt for details.

The Herald Project Team

Herald Project is released as open source software and provides community support through our GitHub project page. If you encounter an issue or have a question, feel free to reach out on the GitHub issues page for Herald Project.

The Herald project team welcomes contributions from the community — please see our contributing documentation.

Getting Started

To help you get started, see the documentation.