What is Wikibase “Federated Properties” in 2025

I recently wrote a post looking at the history of the Wikibase “Federated Properties” feature. While at Wikimania 2025 the topic of federation came up a few times, particularly given the current discussions ongoing on the Wikidata project chat page including discussions about wikicite, and the recent Wikidata graph split.

All the code for the “Federated Properties” feature still exists in Wikibase code, despite a ticket being open on phabricator to potentially delete it. And it turns out that the configuration for it still exists on wikibase.cloud too, where the feature was initially presented to the communities to try out.

So with a little bit of sneaky “hacking”, I can try to summarize the current / final state of the “Federated Properties” feature, after development during the MVP stopped some years ago.

This also means you can still try out the feature on your own wiki using the setting.

$wgWBRepoSettings['federatedPropertiesEnabled'] = true;

Creating a local property

Firstly, we need a property, and the creation workflow is exactly the same as on a normal Wikibase.

List of properties

Trying to list what properties exist on the Wikibase, presents us with the simple List of Properties page implementation from the first version of the feature. Which doesn’t actually show us anything at all, as in the first version, properties could only be used from Wikidata.

Fixing this would likely be trivial, either list the local ones and keep the banner at the top saying some come from another site.

The task for doing something about this is still tracked at T288522: View lists of available properties with Federation v2 enabled

Creating statements

The statement creation workflow is also the same as on a normal Wikibase.

With the exception that the search list contains both the local and any remote properties.

String below is the local property that we created, with every other property being from Wikidata.

Once the property is selected, you can simply enter a value and hit save.

A local and a remote (Wikidata) statement

So, once a local and remote property are saved, you can see them both on the item page.

However, there is a small issue with the presentation of the remote property when saved.

That can be fixed with a quick reload that leads to the page being rendered correctly.

Clicking on the property

Clicking on the property label / link results in a little popup letting you know you are navigating away from the site to view the property info.

There was discussion about actually displaying the property information locally, however that was decided to be unnecessary complexity for the early MVP, and also just maybe not desired at all.

Diff view

Looking at the changes in the diff page, everything looks rather nice, except for the edit summary formatting, which leaves a little to be desired.

History view

The history view also exposes these less than ideal edit summaries.

I imagine that these things are probably tracked under T288562: View revision history page when Federation v2 is enabled

JSON representation

The JSON representation simply uses the full URI for the property in both the keys and property value.

You can find a test version of this output at https://phabricator.wikimedia.org/P80981

TTL representation

And there is currently no integration into the query service, as the TTL representation was not yet done.