Sorry, we’re closing! On October 16th.

TL;DR: We failed at product-market fit; servers will be shut down on 2020-10-16 at 16:10 CEST; a data export function is in the works; all software will be released under an open source license.

Dear Kullo supporter,

it has been a long journey since we started Kullo in late 2012. With the idea of making secure communication accessible to everyone, we reached many milestones such as designing an end-to-end encrypted messaging protocol, launching the desktop apps in 2015, and building mobile applications. Unfortunately, we never found product-market fit. The number of paid accounts as well as the free usage of Kullo remained at a constant low level. The development of Kullo slowed down a few years ago and finally came to a halt since the project was not having enough traction to justify further investment in terms of money and development time. We have been looking into expanding our business into related fields and discussed potential collaborations with other companies, but it didn’t work out in the end. In order to avoid risking bankruptcy of Kullo GmbH, we decided to do a clean liquidation. Consequently, all services provided by Kullo GmbH will be shut down during 2020.

Kullo will be operational until the shutdown on October 16th 2020, 16:10 CEST. When the servers have been shut down, it will be impossible to download or send messages. Already downloaded messages will remain accessible, though.

We are developing an export feature which we will release at some point this spring. It will allow you to export your conversations and attachments. This export feature will only be available in the desktop apps. If you only use Kullo on your phone or tablet, you will need to install the desktop app and download your inbox before October 16th. Please note that syncing the entire inbox can take a while, depending on its size and the speed of your internet connection.

All software that we’ve developed will be available unter an open source license (BSD 3-clause), allowing you to build the Kullo client or server on your own, or just reuse some components of it.

For all shutdown-related questions, the best way to contact us is by sending an email to

This is a sad moment for everybody involved: customers, users, founders, supporters, investors, family and friends. But after carefully considering the options, the best we could do was to ensure a smooth offboarding and a controlled shutdown.

We want to say thank you to all the great people who believed in us and without whom we couldn’t have gotten this project off the ground. They helped us with advice, money and moral support. They gave us opportunities we wouldn’t have had without them. And, last but not least, they advocated for more privacy by using the product and spreading the word. Thank you!

Simon and Daniel