COCOA - COVID-19 Contact App

26.4K reviews
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About this app

This app is for use in Japan.
Officially provided by the Ministry of Health, Labour and Welfare of Japan (MHLW), this app notifies you of close contact with COVID-19 positive users to help the government and healthcare organizations contain the spread of COVID-19.

■ What you can do
Smartphones with this app will emit radio waves via Bluetooth. When other smartphones with this app receive the radio waves, these will be record in the smartphone.
If you are tested COVID-19 positive and have anonymously registered the positive test result, the app will notify users who were within 1 meter for 15 minutes or more during the period of infectivity.
If it was detected that within the people who came in contact with you there was a positive, you will be notified of the possibility of close contact and guided appropriately.

■ Privacy
No personal information such as your name or phone number is collected. No geolocation data including GPS data is collected.
All data is encrypted and saved locally on your smartphone. All data is automatically deleted after 14 days. Your movements cannot be seen in any way by anyone including government agencies or third parties.
You can stop recording close contacts anytime. Turn on recording the settings in the app or delete the app.

■ Recording ‘close contact’
This app records ‘close contact’ across Android and iOS devices by using Bluetooth and Exposure Notification API provided by Google/Apple.
When you run this app, each smartphone generates a random code. This code changes every 10-20 minutes
When smartphones running this app are in close contact, they exchange random codes. Received codes are stored only on the devices.

■ Close contact notifications
Users who tested COVID-19 positive, can choose to share the random codes that their devices have sent out. Each device periodically checks if it has previously encountered any of the shared codes. If the code shared by a COVID-19 positive user matches with a code stored on your device, you will be notified that you have been in close contact with COVID-19 positive user and provides guidance to protect your health.
To receive notifications of close contact with COVID-19 positive users, you need to download this app and enable exposure notification function on OS settings. The app only works with others who have the official app installed.

■ Support in case of contact with positive registrants
To visualize the close contacts select it from the app or the notifications and you can see the contact period with positive registrants during the last 14 days.
If you are a close contact, please enter information such as physical condition from the app using the symptom input form, and you will be appropriately guided.
For those who are unfamiliar with smartphones, you can be guided via phone call.

■ When you tested positive
When you are tested COVID-19 positive, please voluntarily register so in the app to notify other users of potential infection. When healthcare organization registers your positive test results to “The Health Center Real-time Information-sharing System on COVID-19” (known as HER-SYS) provided by MHLW,  a processing number is issued to you. Entering this processing number in the app will allow you to register your positive test result.

■ Stop or delete close contact recording
You can stop recording close contacts with other users anytime by changing app settings. You can delete close contact history (14 days) anytime by deleting the app.

■ Availability
This application will be available until COVID-19 ends.

■ Supported OS versions
Android 6.0 or higher

■ FAQ & Contact
FAQ (Japanese):

■ Privacy Policy & Terms of Use
Privacy Policy(English):
Terms of Use(English):
Updated on
Jun 5, 2022

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
No data shared with third parties
Learn more about how developers declare sharing
No data collected
Learn more about how developers declare collection
Data is encrypted in transit
Data can’t be deleted
26.4K reviews
Gopal Krishan Aggarwal
July 5, 2022
When I tried to register corona positive result with the provided number, it didn't work. It gives an error saying "Incorrect processing number". If corona positive people can't even report they are positive than no point of having this app.
8 people found this review helpful
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Harold Wright
June 16, 2022
I rate this app 5 stars cuz the Japanese govt & health organisations take protecting my health & others very seriously in stopping the spread of the COVID-19 virus & it's variants. Well worded, easy to use & very easy to understand!!! Also, I encourage others to download this app for their wellbeing & to be more at ease in this time of the COVID-19. I applaud the developer of this app. Thank you!!!🤩🥰😇
7 people found this review helpful
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Todd Schmidt
June 19, 2020
Easy install. I always have Bluetooth off unless connected to headphones, so breaking that habit will be difficult. This doesn't work unless Bluetooth is on. Anyone with privacy concerns, none here, but I hope you have turned of GPS location tracking. I'm not sure those people who are concerned about privacy are even aware their location data is being tracked and stored. See Google Maps TimeLine, which I use. Personally I would favor a more aggressive contact tracing app for the case of Corona.
73 people found this review helpful
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What's new

- Updated part of the tutorial
- Improved the wording and design in the app
- Improved the accessibility
- Fixed a minor bug