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Championing open communication
Chat Over IMAP

Open-Xchange is leading the fight to bring back freedom of choice to users and developers by driving the creation of the COI standard.

In a world where chat communication is held in monopolized silos, the COI standard aims to open up the market so that anyone can create, or distribute, open chat applications. This will benefit end users, developers and providers alike.

What is COI

COI (Chat Over IMAP) is a new and open protocol, developed by Open-Xchange, which utilizes existing email servers to deliver chat-based communications.

The main advantage is that any COI compliant app can communicate with any other app, or email client.

Any chat app that has been written using the COI protocol simply connects to an email server and uses an email address to direct the chat data. If the recipient has a COI based client (any COI client works) they see the message in their messaging app. If the recipient does not have a COI client, they will see the chat as an email.

The open messaging opportunity

Messaging applications that use an open email-based standard represent a massive opportunity because they work cross-platform, give access to over 7 billion active email accounts and:

  • Work cross-platform giving access to over 7 billion active email accounts
  • Break down the silos and lock-in created by proprietary messaging standards
  • Break the boundaries between email and messaging allowing exciting new hybrid apps to emerge
  • Encourage the emergence and development of an extended messaging-based app ecosystem
  • Provide opportunities to revitalize existing email infrastructure
  • Reshape the messaging landscape to strengthen existing customer relationships and allow providers to continue engaging with users that would otherwise be lost

The Problem with messaging today

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.


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


Users cannot easily change chat providers. If they want to switch, they need to convince their friends to move too. Also, they would lose their conversation history, groups, and more. Users are stuck: if they do not like something, e.g. a new app version, oh well: you can’t go anywhere else!


Unfair Competition:
Service providers have to comply with the rules set by the messaging owner. If the messaging provider changes the rules or API, they are out of luck and must adapt fast.


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.


Each network is closed and the users in that network are isolated. This means restricted movement between silos, no new innovation outside the controlling power, no new players, no resistance to attacks (single source code) and it simply goes against the philosophy of the internet: freedom, innovation and growth around the use of common standards.

How COI addresses these problems

COI is a distributed system and no one provider knows all about your social networking practices.



Open Ecosystem:
COI is an open protocol that can be adopted by anyone. Success is governed by the practicality of the application.  


No Lock-in:
As COI is a cross platform and open protocol, users can easily change chat applications without needing to convince their friends to move too. Loyalty is driven by functionality and performance.



Fair Competition:
Just like IMAP, COI is an open and published standard. As such it has to comply with usual practices such as backward compatibility. This means service providers are always free to change at their own pace.


Your Choice:
As COI is an open and cross platform standard, that is easy to use, it is envisaged that diversity and choice of chat-based applications will significantly increase.


No Silos:
The whole concept of COI was created to break down the walls of silos and free developers, users and providers to embrace freedom, innovation and growth around the use of a common standard.

COI Benefits




COI Benefits for











The adoption of COI, updates to Dovecot and OX App Suite and the extra offering from Open-Xchange will help Open-Xchange customers by:

  • Providing more functionality within OX App Suite
  • Increasing activity of existing users
  • Increasing activation of users in general
  • Increasing opportunities to upgrade users
  • Providing a more complete service
  • Attracting new demographics


The creation of COI not only helps in Open-Xchange’s fight for a free and open Internet but will also benefit Open-Xchange customers too.  

While creating COI Open-Xchange will also expand:

  • The capabilities of its Dovecot server range
  • The functionality of its OX App Suite platform
  • The white labeled apps it provides for its customers to use



COI Benefits for











The COI protocol aims to remove many of the barriers found today, to free up developers and help them become more creative.

Key features of COI for developers are:

  • Developers do not need to build, deploy or maintain a server
  • Developers can focus on functionality and not on communication
  • Client developers can now focus on what they are good at: building clients
  • Any COI application can chat to any other COI application using email addresses
  • Developers can now focus on innovation and not marketing
  • Developers no longer have to entice users to join their new ecosystem
  • The ecosystem is already there with 7 billion active email accounts
  • The COI API is high level and flexible

For a more technical overview of COI, please go to



COI Benefits for











The successful adoption of COI should have a significant impact on consumers.

  • You are free to use any chat client of your choice without restriction
  • Users will have more choice as they are now free to use any chat client
  • All email and chat messages are in one place, so users can easily find what they are looking for
  • Reach almost anyone in the world, email has significantly more users than any other messaging platform
  • Select the messaging provider that you trust, not the one that comes bundled with your app
  • Communicate safely

Open-Xchange is working closely with partners to produce the first COI based applications. Open-Xchange will also release its own open source application as well as white-labled commercial applications.

Why Open-Xchange
Invests in COI

COI is the result of Open-Xchange initially wanting to extend both OX App Suite and its range of mobile apps. After identifying the closed state of the chat market Open-Xchange decided to try and break down this walled market while fulfilling its own need for chat applications.

Open-Xchange will offer COI based chat applications to its customers. Apart from offering a more complete service this should help providers better utilize their existing email infrastructure, strengthen customer relationships and allow them to engage with users that might otherwise be lost.

The ultimate vision is to create an open market for chat-based applications where users get a better experience with no lock-in; developers are free to enter the market and drive innovation through variety; providers deliver a better and more complete service and the market as a whole grows in quality and suitability.

Visit our COI Developer Page

COI Developer Page

Visit the COI GitHub Repository

GitHub Repository

Join the COI mailing list


Visit our COI News page

COI News