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   OX COI Messenger

Email has never been so instant.

Discover how we plan to chat via email with OX COI Messenger. See our progress, join the community to test the latest beta version of the OX COI Messenger app here.

Join the OX COI Messenger beta.

We are reopening the OX COI Messenger beta to anyone who wants to try our latest messaging app (iOS or Android).

For Android just go to the Google Play Store, for iPhone you first have to install TestFlight.

You don’t need a special account; it just sits on top of your email account. We do not hold your data, it is simply stored in your email account.

Please let us know what you think and be as honest as you can: oxcoimessenger(at)

Thank you from your COI Team

No sign-up needed.

You can use any email account and start chatting right away. Keep in touch with all your friends, family and colleagues. If they do not have the COI Messenger app yet, they will still get your messages – as emails.

Send media files and stay secure.

Send and receive texts, voice messages, photos or documents. Your messages are encrypted automatically.

Stay in control.

OX COI Messenger works with any email provider. You choose whom to trust and where your data is processed and stored. Your credentials never leave your phone.

OX COI Messenger Beta

This short video shows how email can look by using the new OX COI Messenger. The video takes you through all the main features and introduces you to the new face of email.

Introducing COI

This bootleg video was taken at the Open-Xchange Summit in Madrid where CEO Rafael Laguna and PM Robert Virkus explain how COI was taken from conception to Beta.

Built Using the COI Standard.

The OX COI Messenger beta is built on top of the COI standard and in Collaboration with Delta Chat. Under the covers it uses an adapted version of the Delta Chat Core component. The COI standard can be found on our COI GitHub page and the OX COI Messenger beta can be found on our OX COI Messenger GitHub page.