Drive and Collaborative document editing

OnlyOffice Docs

OnlyOffice Docs primarily works with the OOXML formats (.docx, .pptx, .xlsx, ...) from Microsoft. It is widely considered to be the best and most reliable implementation of OOXML formats outside Microsoft Office. OnlyOffice can only open ODF (.odt, .odp, .ods, ...) files in read only mode, it must first convert them to OOXML before they can be edited. When saving the documents, OnlyOffice allows exporting them back to ODF format. Converting from one file format to another will lead to some formatting issues which may alter the document's overall appearance. This is particularly visible in long and/or complex documents and presentations, where small differences may amplify each other. The content itself is unaffected by the conversion process.
OnlyOffice brands itself as Free and Open Source Software (FOSS), but there have been some issues regarding both the way the project is licensed ^[1], and the way it is handled, with critics claiming that the development process isn't open at all^[2]. This, alongside some geopolitics (the project has Russian roots), led to the creation of the (not yet fully released) Euro-Office fork.

OnlyOffice operates using a client-side document editor that regularly synchronises the changes made by the user back to the server. This approach allows editing without any of the latency that usually comes with a cloud service and offers a snappier experience. It also means that in case of loss of connection, you can keep on editing your document without interruption. On the other hand, this approach can cause a loss of work if the connection is not properly re-established after an interruption. It also means that other users contributions might appear in blocks rather than as they type, leading to slightly harder collaboration and risk of conflict.

The OnlyOffice desktop and mobile app can interface directly with various cloud providers, including but not limited to Nextcloud, ownCloud, DropBox, Moodle and Seafile. The usefulness of this feature is situational as in most cases you would have your cloud storage mounted as an extra drive, but it remains a nice to have.
OnlyOffice also offers a fully fledged PDF editor and AI integration, using both global providers (OpenAI, Anthropic, Gemini, DeepSeek, etc...) and ones you can host yourself such as Ollama and LM Studio. I haven't tried this feature.

Collabora Online

Collabora Online is a FOSS project throughout. It is based on LibreOffice, which provides the document editing capabilities, with Collabora bringing the extra tooling required for online collaborative editing, as well as a different interface. Being LibreOffice based, Collabora uses ODF by default. Documents in Microsoft's OOXML format are also supported, they can be opened, edited and exported natively, without conversion process, but their formatting is likely to appear different than on Microsoft Office. Just like with OnlyOffice, this is particularly noticeable on long and/or complex documents, where small differences add up, but the content itself is not affected.

Collabora Online uses a fairly classic client-server architecture. Documents live on the server side and are never sent to the client, the client only receives rendered images of what the document looks like, the client can then send edits that are applied on the server.
The advantages of this approach are that as edits happen exclusively on the server, conflicts are much less likely and easier to resolve than with OnlyOffice's approach. Collabora also claims that it allows for finer access control, with the possibility to watermark the images the clients receive to track potential leaks.
On the other hand, this design choice means that the slightest loss of connection will stop your work for its duration. It also means that opening files is slightly slower, as the server needs to render and send it in image format before the user can properly interact with them. Finally, the experience is not very snappy, as the user experiences a small but noticeable input delay on every action. It is particularly noticeable when making changes that affect a large area, such as changing the font of an entire paragraph for example.
In one of its few departures from Microsoft Office's look, Collabora chooses to dynamically group its functionalities in various submenus depending on the window size, improving readability for small screens, at the cost of confusing new users who might wonder where all of their options went! Collabora also offers an alternative "compact" interface that is somewhat reminiscent of the controls you get on mobile.

Collabora also includes a vector graphics editor based on LibreOffice Draw in its suite of application. It is primarily marketed as a diagram editor and an alternative to tools like draw.io. While most of its features are already included in the document and presentation editors, it remains useful for creating content that can be reused across multiple documents.

My preference

Let's start by stating that Collabora Online and OnlyOffice Docs provide essentially identical core functionalities, and I am satisfied with both of them. Personally, I prefer using ODF file formats, and dislike having to convert my files from one format to another to be able to edit them. This is an advantage for Collabora. However, Collabora's interface has a significantly larger input delay than OnlyOffice, which makes it less pleasant to use. Assuming a decent internet connection, it seems to me that OnlyOffice's architecture offers less drawbacks than Collabora's.
On the server side, OnlyOffice depends on multiple external services, including two databases (PostgreSQL and Redis) and message broker (RabbitMQ). Collabora, on the other hand; is pretty much monolithic, which makes it theoretically easier to host and integrate. In practice, for small deployments such as mine, OnlyOffice provides a single docker container with all the services backed in (Which goes against the principle of containerization: one container per service. Disgusting, I know, but it's convenient). In many cases, the software Collabora or OnlyOffice integrates with will offer a one click (or at least very easy) install for the service, making the complexity of deploying the standalone version completely irrelevant.
In conclusion, I do not really care, both are fine though imperfect. My server has enough ressources to handle Collabora, and the hassle of converting files from one format to another with OnlyOffice feels about as annoying as Collabora's input delay. I'll be happy to use whichever one integrates best with the file storage software I use.

My ideal collaborative document editor would have OnlyOffice's low latency and resource usage while using the ODF file formats as defaults and maintaining compatibility with OOXML formats. Luckily for me, this is one of the Euro-Office project main objectives! So I'll probably have a very good look at it when it releases!

Comparison to non self-hosted options

Google Workspace

I think this one is very straightforward. In my opinion, other than its integration with the whole Google ecosystem, and the fact that everyone already has a Google account, there is nothing that Google Workspace does better than OnlyOffice or Collabora. Google Workspace uses its own proprietary file formats, so a conversion or export is required for cross-compatibility with other software. Furthermore, Google Workspace suffers from the same, if not worse, formatting issues when converting files. Finally, in terms of functionalities, Google Workspace applications are much more limited than the alternatives.

Microsoft Office 365

Microsoft Office 365, or whatever Microsoft has decided to call it this week, has been the standard for many years, and for good reason: it has a good interface, a complete feature set, and you can be confident that anyone on earth who opens your file will see it exactly the way you designed it. While this last point is not quite as true as it was 10 years ago, but OOXML documents remain by far the most widely used format.
Just like Google Workspace, Microsoft Office benefits from being integrated with the wider Microsoft ecosystem. Even when focusing on the core functionality it isn't easy to find something that the alternatives do better, still, I can find a few. First and very obviously comes the support for ODF formats. Secondly there is the Linux support, as Microsoft does not offer native apps for it. Finally and most importantly, the online editors for OnlyOffice and Collabora are more powerful than Microsoft Office's, which has slightly limited functionality compared to the native application. However, this difference will only be noticeable to the most advanced users.

While there is very little that OnlyOffice and Collabora do better than MS Office, there isn't that much they do worse either! If you look it up, MS Office is still the most powerful option, especially Excel, but unless you know what a "Power Pivot" is, you will probably never notice. Notable exceptions are the built-in translation feature, and the "morph" transition in PowerPoint. For compatibility's sake, it must also be noted that MS Office, Collabora and OnlyOffice all use different languages for macros.

CryptPad

When I first set up my server, CryptPad was the first "Drive" software I ran. The reasoning behind my choice was: "I need something that works, I'll find the option that suits me best later". In other words, I chose it almost randomly. This temporary solution has proven quite definitive so far, as I still haven't finished testing all the other options. So, what does CryptPad do?
CryptPad is a FOSS, collaborative productivity suite with end-to-end encryption. It integrates OnlyOffice for document editing and draw.io for diagrams. CryptPad also offers its own tools for Kanban boards, a whiteboard, rich text, Markdown and HTML editors with a preview function. There is also a very powerful form builder that can export results to multiple formats, including directly to a spreadsheet. In addition to document-related functionalities, CryptPad includes a calendar, team spaces and a contacts book. This is a very comprehensive set of features.

CryptPad's biggest selling point compared to the alternatives is its end-to-end encryption, but it also has a few drawbacks. First among them is the lack of offline applications. Due to the encryption, neither the OnlyOffice app nor generic file synchronisation tools can interface with it. As CryptPad does not provide its own apps, it can exclusively be used online, in a web browser. This means that it cannot automatically synchronise files to and from remote storage, and does not provide all the features I am looking for. I have been using Syncthing to make up for this. It must also be noted that I am already hosting services that are not end-to-end encrypted, meaning the users of my server already trust me with their data, which somewhat defeats the purpose of end-to-end encryption.
CryptPad would be great for enterprise use, either as a self-hosted service, or using one of the public instances, where end-to-end encryption would be truly useful. For my specific use case however, it isn't ideal.

Other options I haven't tried (yet)

• ownCloud
• SeaFile
• Sync-in
• OxiCloud
• OpenCloud
• and a lot more...