Nextcloud is a powerful self-hosted collaboration suite—but by default, it lacks the ability to edit Office documents like Word, Excel, or PowerPoint directly in the browser. OnlyOffice fills this gap by providing a robust, Microsoft-compatible document editor you can run on your own infrastructure.

In this blog post, we’ll walk through the process of integrating a self-hosted OnlyOffice server with a Nextcloud instance. This guide covers the installation of the OnlyOffice app in Nextcloud and the necessary configuration to link the two systems.

• Requirements
• Step 1: Install the OnlyOffice App in Nextcloud
• Step 2: Configure the OnlyOffice Integration
• Step 3: Verify the Integration
• Conclusion

Requirements

• A working Nextcloud instance (version 20+ recommended)
• A separate, self-hosted OnlyOffice Document Server
• HTTPS certificates on the OnlyOffice server
• Access to both servers via browser and terminal
• Admin privileges in your Nextcloud instance

Step 1: Install the OnlyOffice App in Nextcloud

To enable integration between Nextcloud and your OnlyOffice server:

• Log in to your Nextcloud web interface as an admin user.
• Click your profile picture in the top-right corner, then go to Apps.
• In the left-hand menu, click Tools.
• Search for OnlyOffice using the search bar.
• Click Download and enable.

This installs the official OnlyOffice integration app within your Nextcloud system.

Step 2: Configure the OnlyOffice Integration

Once the app is installed:

• Go to Settings > Administration > ONLYOFFICE.

• Enter the following values:

  • ONLYOFFICE Docs address:
    https://onlyoffice.domain.org/

  • Secret key:
    Copy this from your OnlyOffice server’s configuration file:
    /etc/onlyoffice/documentserver/local.json

    Look for the secret field under any section (inbox, outbox, or session) — the value is the same in all of them.

  • Authorization header:
    AuthorizationJWT

• Click Save.

Step 3: Verify the Integration

Now that everything is connected:

• Navigate to your Files section in Nextcloud.
• Upload a .docx, .xlsx, or .pptx file.
• Click on the file — it should open in the browser using OnlyOffice.

You can now create and edit documents inside of Nextcloud. Without OnlyOffice, this feature is not available.

Conclusion

Connecting OnlyOffice to your Nextcloud server enables powerful in-browser editing of Office documents, completely self-hosted and under your control. With just a few steps — installing the app, configuring the connection, and setting the shared secret—you unlock seamless integration between file storage and document editing.

If you’re looking for a secure and private Google Docs alternative, this setup is a great place to start.

📝 For more information about this integration, please review About the ONLYOFFICE and Nextcloud integration.