Between 2015 and 2023, editors could use the Graph extension to visualize data across Wikimedia projects. Hundreds of thousands of Wikipedia articles contained these graphs as a way to enrich the text-heavy content of the wikis. In 2023, the extension was disabled for security reasons. This left editors frustrated that readers were unable to view graphs that they have invested time and energy into creating.

The Wikimedia Foundation discussed the future of graphs with community members, and this project is the outcome of those discussions. We are building a new secure tool, which we are calling Chart, as a successor to the Graph extension. It will handle the majority of simple data visualization uses on Wikipedia articles. The new tool will be built in a way that will make it easy to add support for more use cases in the future if the Foundation or community developers choose to do so. We will know we’ve achieved success when editors are converting old graphs using the new tool.

In the 2024–2025 Annual Plan, the Charts project is documented as the key result Wiki Experiences 3.3.

Deployment Timeline

The extension will be rolled out to wikis incrementally. It is already available on a select list of pilot wikis. The focus for the next wave of availability will be on the remaining Wikipedias. The rollout will start with most Wikipedias, moving then to ones that were heavy Graph users, and ending with some of the largest ones. These dates are subject to change as we track issues and monitor system performance during the rollout.

Phase	Wiki	Dates	Status
Pilot	Hebrew Wikipedia [he] Italian Wikipedia [it] Swedish Wikipedia [sv] MediaWiki	4 Dec 2024	Done
Phase 1	All Wikipedias except those listed in Phases 2 & 3	6–8 May 2025	Done
Phase 2	Russian Wikipedia [ru] Chechen Wikipedia [ce] Tatar Wikipedia [tt] Ukrainian Wikipedia [uk] Armenian Wikipedia [hy] Basque Wikipedia [eu]	13–15 May 2025	Done
Phase 3	English Wikipedia [en] French Wikipedia [fr] Spanish Wikipedia [es] German Wikipedia [de]	20–22 May 2025	Done
Phase 4	All other non-Wikipedia wikis hosted by WMF	27–29 May 2025	Done

Strategy

• Audience. We are guided by the needs of Wikipedia readers. We will focus on the most common uses of data visualization for enhancing encyclopedic content. This means that uses outside of articles, such as for PageViews, are not a priority now. However, although the primary focus will be on Wikipedia articles, charts will not be limited to pages in the main namespace and will be available on non-Wikipedia wikis.
• Ease of use. We want to make it easy for any editor to be able to create a chart intuitively. Previously, it was fairly difficult to add and edit graphs. Editors needed to be comfortable interacting with Vega, the underlying software powering graphs. This is why editors created most graphs using templates that contained pre-defined Vega code. Templates are more user-friendly, but cannot be easily reused across wikis. This time, different types of charts will be defined by the tool and will be available across all wikis. Editors will be able to add charts using a familiar wikitext format and will not need technical knowledge about the software underneath. These changes will reduce the need to rely on templates. They will also make it possible to upgrade the underlying library without disrupting existing charts.
• Architecture. Charts will be rendered (turned from code into visual content) on the Wikimedia Foundation servers using an open-source data visualization library, generated from data pulled from defined sources. More specifically:
  • Rendering charts on our servers will allow for pages to be loaded quickly. It also avoids the security issues that we faced with the graph extension. It will also enable charts to appear on the mobile apps, in exports, and in other reuse/offline scenarios.
  • For data visualization, charts will be generated using an open-source library. This library must meet our requirements like support for different languages, some level of interactivity, color customization, and more.
  • At first, there will be a single data source for charts: pages in the Data namespace on Wikimedia Commons. This will make it easy to reuse data between charts, avoiding the clutter of having the data inlined in wikitext. We will also design the system to support adding more data sources in the future.
• Editor support. This project will only succeed if editors convert existing graph code to charts and start creating new charts. We will find ways to support editors with converting existing graphs through automated and manual processes. We will also look for ways to preserve existing graphs that are unlikely to be converted to charts. This may mean replacing them with static images or transitioning their use case to other tools.

Updates

People

• 
  Chris Ciufo
  Product Manager
• 
  Seddon
  Engineering Manager
• 
  Roan Kattouw
  Tech Lead
• 
  Jon Robson
  Tech Lead
• 
  Brooke Vibber
  Engineer
• 
  Katie Filbert
  Engineer
• 
  Chris Danis
  Site Reliability Engineer
• 
  Derek Torsani
  Designer
• 
  Luca Martinelli
  Movement Communications

FAQ

What is the timeline of the project?

The Chart extension is now available on all Wikimedia wikis. This project is part of the FY24-25 annual plan and will conclude at the end of June 2025.

Which library will be used to render charts?

The Chart extension currently uses the Apache eCharts library. However, if there are unresolvable issues with eCharts, there is the possibility of switching to Vega (the library previously used for the Graphs extension). There is also the possibility of using eCharts for most chart types, but using a different library for certain specific chart types if it turns out to be much better than eCharts.

For details on why eCharts was chosen, and why Vega is considered the only reasonable alternative, see T368336#9971574.

What types of charts will be supported?

There will initially be a limited set of supported chart types: line, area, bar, and pie charts. The latest documentation is available on Extension:Chart page.

Where will chart definitions be stored? Where do I go if I want to edit a particular chart?

Chart definitions will live on their own .chart pages on Commons, under the Data: namespace. Charts will be treated as a standalone content type, rather than just as part of an article. It will be easy to reuse the same chart across wikis, and beyond Wikimedia platforms by making them available as links. Editors who want to embed charts in an article will be able to do so with a short piece of wikitext, similar to including an image from Commons, without needing to interact with complex templates.

One weakness of requiring that the data come from Commons tabular data is that data sourcing flows such as from MediaWiki APIs or Wikidata Query Service are not handled. While those sources are not the focus for this project, this project aims to design the extension in a way that they can be supported in the future.

How can volunteers add more chart types?

Once the initial infrastructure exists to create charts, technical volunteers will be welcome to contribute more chart types. In the meantime, you are encouraged to tell the developers what you think – which types of charts are most important to add next.

What will happen with the existing graphs?

For now, the existing graphs will remain in their current state. Some wikis have chosen to hide graphs entirely while others render a message explaining that graphs are disabled. Once it's possible to create charts that can replace graph uses, Chart extension developers will work with volunteers to start converting them so that readers can start to see them again.

It is unlikely that all graphs will be able to be converted to charts. For graphs that cannot be converted, it may be more beneficial to either: find an alternative tool to recreate the graph, convert the graph to a static image, or remove the graph altogether.

How to produce the charts efficiently?

There are several conceivable methods to semi-automatically produce and edit the charts and their tabular data:

• The script graphDataImport can be used in the web browser to extract data from existing graph wikicode, and convert it to a .tab page, and a .chart definition page.
• Generative AI can be prompted to extract data from existing graph wikicode and tables, and convert it to .tab and .chart pages and generate new wikicode, according to given specifications. It can also provide translation of titles, and be utilized to extend and update the .tab page with new data.
• The gadget TabularImportExport can convert Excel and .csv files to and from the .tab pages. You can activate it via your Commons preferences.
• The JSON "edit as table" user interface (part of the Jsonconfig extension) is available from the .tab edit page.
• Some bots can periodically import statistics from the web, or from existing Wikipedia graphs, to .tab or .chart pages, upon request. Such bots include GraphBot, DPLA bot and SLiuBot.

What templates and modules are available It should be possible to use extension:chart without a multitude of local templates and modules. However, here are some templates and modules that are related to this extension:

• en:Template:ChartDisplay.

Get involved

• Subscribe to the newsletter to get notified about new project updates and other news