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What is ChasR?

ChasR is an open-source end-to-end encrypted GPS tracking system. It allows you to track devices and watch the tracked devices in real time. It can be used as part of the AlertR alarm and monitoring system (for example if you want to build a car alarm system), but works also completely without it.

Diagram showing the ChasR architecture:
a logger device for collecting the location data,
the server that stores the encrypted data,
and the map device showing the location data.

You may ask: why build a new GPS tracking system when there are so many that are free to use and store your data in the cloud? First of all, cloud is just a fancy marketing term for store your data on someone else's computer. So do you want to store all your location data plainly on my computer? I do not think so. And all the services out there I found just did this: no encryption, just plainly uploading the location data to the server. Therefore, the idea to build a new GPS tracking system. The system still uploads the data to a server (or the cloud if you prefer marketing terms), but ChasR encrypts the data on your client before it is uploaded. As a result, only people that know the secret key you used to encrypt your data can access it. This circumstance is meant when I say end-to-end encrypted.

Also, if you are a developer you can integrate GPS tracking easily into your project. ChasR offers a documented API for all developers and tinkerers who want to integrate it.

The vision for ChasR

The vision for ChasR is to provide a GPS tracking service that protects the privacy of its users. Nothing more, nothing less.

How does it work?

To use the ChasR GPS tracking system, you have to register a free account or host the server yourself. Then you install the logger application on the device you want to track (for example an Android phone). The logger application will send each GPS location encrypted to the server which stores it. To see the stored location data, you either install the ChasR map application on your device (for example your Android tablet) or use your web browser.

Shortly summarized: the logger application gathers the location data, the server stores the encrypted location data, and the map application shows you the location data.

If you have further questions, please see our FAQ for details.

Where can I get it?

Each component of ChasR is available as source code or can be directly installed using the different App stores. Please follow the link of the corresponding component you want to use.

ChasR Logger

The logger application tracks the location on a device.



ChasR Map

The map application shows the location of the tracked devices.



ChasR Server

The server stores the encrypted location data. It is only needed if you want to host the service yourself.

Supporting ChasR

If you like this project you can help to support it by contributing to it. You can contribute by writing tutorials, creating and documenting exciting new ideas to use ChasR (e.g., on Reddit), writing code for it, and so on.

If you do not know how to do any of it or do not have the time, you can support the project by donating or support me on Patreon. Since this service has a monthly upkeep, the donation helps to keep it free for everyone.




Why do I need a ChasR account to use it?

The location data tracked by your logger devices is stored on the ChasR server. So in order to keep your data only accessible by you, you need a ChasR account.

For what do I need this secret in my settings?

The secret is used as a key to encrypt the location data on your logger devices and the same secret is needed on your map devices to decrypt the location data. This mechanism allows ChasR to establish an end-to-end encrypted data transfer which lets the server in the dark about your location.

What do the Device Slots mean?

The Device Slots are the number of available devices you can track and store on the server. Since the ChasR GPS tracking system is a free service for everyone, I have to limit the resources each user can use (since my sever only has a limited capacity). If you want to store more devices, you can support me on Patreon to unlock new Device Slots or contact me directly.

How long is my location data stored on the server?

Your location data is stored for 365 days. As soon as it is older than that, it is automatically deleted. Obviously, you are free to delete your location data manually before this age is reached.

Can I host the ChasR server myself?

Of course you can. The source code for the ChasR server is available on Github. Just remember to configure your logger and map devices to use your server instead of the official one.

What is this AlertR and what does it have to do with the GPS tracking?

The short and simple answer is: nothing. You can use ChasR without knowing what AlertR is.

The longer answer is: ChasR uses the infrastructure of AlertR (server and account management). Furthermore, the whole idea of ChasR started as part of the AlertR Monitoring and Alarm System. AlertR is great to monitor your home and services you operate by giving you a framework to integrate everything. The next thing I wanted to monitor was the location of my car (to know the location and as an anti-theft mechanism) and I was checking out existing GPS tracking systems. None of them provided me with end-to-end encryption to protect my privacy and so the idea of ChasR was born.


If you want to reach me, have any questions, feedback or bugs, please use the GitHub Issues or Twitter.