COI Soon to Become Reality

Oct 1, 2019

The Open-Xchange COI (Chat Over IMAP) project, launched to create a new and open alternative to chat, is reaching a major milestone. Both a COI-enabled Dovecot email sever and an open source COI app have recently entered the Open-Xchange QA labs for testing!

Why Does the World Need a New Chat App?

Three main areas of concern have been identified when it comes to instant messaging.

Limited Privacy: the provider knows all about your social network, when you communicate, with whom, the frequency of your communication and the number, type and length of your messages, even with end-to-end encryption in place.

No Choice: some large providers control many of the popular messaging apps. For example, Facebook owns both WhatsApp and Facebook Messenger. This makes it feel like there is no real choice.

Closed Ecosystem: a single party controls these networks. Developers cannot start hosting their own WhatsApp, WeChat or FB Messenger Service. Competition and innovation is blocked.


What is COI?

COI itself is a new standard that defines how instant messaging apps can communicate with each other by using the existing email infrastructure. This means that anyone with an email address can chat with anyone else with an email address.

Open-Xchange and the Dovecot team have led the creation of this new instant messaging standard. To expedite the uptake of the standard, Open-Xchange has also built an open source app that uses COI.


How Does COI Work?

The COI chat standard is built on top of the current email protocols (IMAP & SMTP).

Emails are normally sent using an SMTP server that delivers emails to the recipients IMAP server. The user then retrieves emails from the IMAP server. COI uses this same mechanism to transmit chat messages.


Why COI?

Email is the most universal and popular messaging system in the world. It has far more active users than any other competing messaging service (7 billion accounts with around 4 billion active users).

Email is open and free: anyone can use it, and anyone can build/implement their own apps and services on top of it. Users are free to choose their preferred provider and free to choose what app they want to use. They are not restricted to one single provider or one single solution.

This is why this widely available and open infrastructure is perfect for building an open chat system on top of it.


Advantages of COI

The main advantages of COI are: any COI app can communicate with any other COI or email app; COI apps can use the existing global email infrastructure; COI apps use email addresses as unique identifiers and the app does not need to handle this job.


Who is COI For?

The COI project actually has three groups of people who will be interested in its adoption:

Developers: COI makes chat application development so simple, which has generated a lot of interest from the development community. This stretches from solo app developers to larger organizations.

Hosters/Providers: COI uses email as a transfer protocol, so hosters and providers see this as a way to reactivate dormant accounts or to stimulate use of email.

Open-Xchange Customers: once complete, Open-Xchange will offer the chat app to customers for branding and distribution.



The COI project was officially started at the end of last year, and since then we have achieved a lot.

  • January 2019: Limited COI partnership started; meeting in Germany
  • February 2019: COI announced
  • February 2019: COI Client Specification published
  • February 2019: First OX COI Messenger app preview published
  • February through October 2019: Many OX COI Messenger preview updates
  • August 2019: COI Server Specification published
  • September 2019: COI & OX COI Messenger integration testing

Next on the list are the following:

  • OX COI Messenger functional feature set freeze
  • OX COI Messenger Android Beta live on Google Play
  • Launch a COI Partner Program
  • OX COI Messenger iOS Beta

In the last few days we have passed all our work onto the Open-Xchange QA team. All this work, the app and the server, are now getting tested. Depending on the results from QA, we are considering creating an official beta for both the server and the app, releasing the beta to the world and creating a partner program for COI.

Watch this space for more information, visit the OX Summit or write to coi(at) to find out more.

About this article

About the Author

Robert Virkus

Robert Virkus

Director Apps Development

Share this article