Nantes 2025

The Gephi Week aspires to be a yearly event where the team and some community members gather to work on the project. The first iteration was in 2021 in Copenhagen (see debrief), and it has happened every year since except in 2023. This year’s edition was hosted by OuestWare in Nantes, France (OuestWare is the team developing Gephi Lite, but it is also a company that does a lot of other projects). The working space was sponsored by the Nantes company UmanIT.

Here is a debrief of what we have done during this edition!

Cover picture: the Gephi Week 2025 team (Martin Grandjean)

1. Gephi ecosystem

New Gephi Lite 1.0

Gephi Lite has been out and running for a while now, and it is now time for a complete UX overhaul! The team (Alexis Jacomy, Paul Girard and Benoit Simard) worked with Arthur Desaintjan a (UX design intern) for a semester to rethink the entire user interface, taking into account the feedback of many users. From this process came out a brand new visual language and layout for the tool, that we are very excited to release very soon. Learn more about this design process in this blog post.

Because we think Gephi Lite will be complete enough, it will move into “1.0” territory. Gephi Desktop was overtaken! More on Gephi Lite 1.0 in a separate post.

▲ The OuestWare team, behind Gephi Lite. Photos: Matthieu Totet

Headless Gephi with Python : Gephipy

A recurrent demand by members of the community is to have an automated pipeline for Gephi-based analysis. During Gephi Week, this concern was reiterated by our colleagues at Agoratlas, Mathis Hammel, Florent Lefebvre, and Clément Hammel.

We do think that Gephi is, by essence, always about visual and interactive user interface. Nevertheless, it’s an interesting and recurring discussion that we had with users. The current official solution would be to use the Gephi toolkit, a headless (= no ui) version of Gephi that allows you to use all Gephi features in your own java application. It’s convenient for Java developers, but most Gephi users are more used to Python using Jupyter Notebook.

So Benoît Simard, with the help of Matthieu Totet, had a quick look on the state of art of interfacing Python and Java and found JPype. This library allows you to load a java library into a Python environment and use it as a normal python library.

It does work nicely out of the box, but then it has been noticed the way to use the toolbox isn’t quite straight forward and it could be simplified so that there would be a more Pythonic way to use the library.

The result of this is a library : Gephipy. This library is available on Pypi and is a wrapper around the Gephi java toolkit that allows you to use Gephi functionality in a Python script or in a Jupyter Notebook.

Keep in mind it’s just an experiment that we make it available and open source so people have a starting point if they need to develop with the headless use case in mind. There is definitely still a lot to do and continue to have a proper python wrapper, but if you are courageous enough, it’s technically possible to use Gephi as a Python library !

At this occasion, we also started the creation of a Gephi organization in PyPI (pending for approval).

▲ As Matthieu Totet is our official photographer, there are few photos of him working on Gephipy, but here is some evidence that it was tiring work requiring mental preparation. Photos: Martin Grandjean

New Viz engine integration

For many years, our lead dev Eduardo Ramos Ibanez has been working on a new visualization engine for Gephi (desktop). This was already an important point of the first Gephi Week in 2021.

Maintenance and performance are at stake. The current engine’s technology dating back to 2008, we had decided to rewrite it from scratch. That way, we could leverage modern OpenGL versions and unlock greater performance. Rewriting a core Gephi module is never easy but we have done it before and doing so also unlocks future improvements and enhanced maintainability. The new engine had been worked in a separate repository, to iterate faster. Prior to the Gephi Week, we had decided that it was now time to finish the integration work and clean-up all of the old engine’s code.

Mathieu Bastian, Matthieu Totet and Eduardo Ramos Ibanez have made a lot of progress in the integration work. The last big missing piece is to render text, and hope to tackle that soon.

Preparing for Gephi 0.11

Integrating the new visualization engine and enhancing its reliability and performance is the main goal for the next Gephi release. We hope to be able to release the 0.11 version by the end of this year.

We also performed maintenance tasks and small improvements, to ensure the software remains up-to-date. Notably, we migrated to the latest version of the Netbeans Platform.

Gephi Web Viewer

We discussed the opportunity to create a new Gephi tool. Sharing a network from Gephi on the web for reading has been a thing from the very beginning (Girard et al. 2024). Recently we added a plugin in Gephi desktop to export a graph on the web using Retina, so we discussed the opportunity to transform Retina into an official Gephi web viewer that could be used from Gephi or Gephi Lite.

Change the icons in Gephi Desktop

Gephi had been using pixel-based icons like in the 90s. It was pretty ugly, even though some may find it charming. That will be gone: we replaced all the icons with a homogeneous design language, following the suggestions of Côme Brocas in 2021.

These new icons will be compatible with the dark mode, and will make the UI more calm, allowing you to better focus on your network.

2. Communication and community

Revamping the website

We had not changed the Gephi website in a very long while!

The main screenshot was outdated by a decade or so… But most importantly, we wanted to make it clear that Gephi Lite was there, and we wanted to make room for it. Our main goal was to have a clear path to Gephi Lite from the landing page.And of course many things ensued, such as redefining the structure of the website etc. We tried to reduce the amount of pages to ease maintenance while making sure all important information is there. We used Astro as an infrastructure to build the new version.

▲ Co-designing a new website for Gephi requires great creative minds… and coffee. Photos: Matthieu Totet

Writing new tutorials

Even if the interface and user experience are well designed, a tool as complex as Gephi must be documented with tutorials. But the Gephi team already has a lot on its plate and the more pages and resources we create, the more things we have to maintain, so we have always been grateful for the community to have written multiple series of great tutorials. We encourage all users to produce their own tutorials, because what novice users need is not always technical documentation but a walkthrough of the main features, in an order and using teaching methods that may be specific to different areas of application.

However, we do think that it is also important to new users that they can find the most basic tutorials on the website directly. It’s important to note that we are about to have new user interface choices for both Gephi Lite (major rework) and Gephi Desktop (minor changes but still significant). This called for making an up to date version of the basic tutorials.

That’s why we decided to create a short introduction to Gephi, as simple and universal as possible. This was taken in charge by a few prolific tutorial makers in the community, namely Martin Grandjean, Veronica Espinoza, and Tommaso Venturini. We decided to go for parallel tutorials between the Desktop and Lite versions of Gephi to help users knowing one going to the other.

▲ Gephi tutorials: Less talk and more shared documents! Photos: Matthieu Totet

New FAQ

You probably know about the strength of weak ties, Granovetter’s famous argument. In short, in your relational network, people less close to you (weak ties) can reach resources you don’t otherwise have access to (they are strong).

We had the chance to have Veronica Espinoza with us. In case you don’t know her, she has been writing a lot on various network analysis tools for PhD students and social science and humanities scholars. And she’s based in Mexico. Precisely because she is confronted to a public that we don’t usually have access to, she had a set of very fruitful comments on Gephi as a tool and as a project. A good illustration of Granovetter’s principle!

We have used her feedback as the basis for a FAQ section in the new website, about using Gephi, but also about a range of other things related to the project or the community.

▲ Discussing user needs and frequently asked questions. Photos: Matthieu Totet

Documentation

In 2022, during the Gephi Week in Paris, we had set up a new online platform to host the documentation. But we had not used it much yet. Progress in the project created that need again, and we decided to definitively move in this new infrastructure.

We decommissioned the old Gephi Wiki, which we froze into an accessible archive.

We will release the new documentation portal with the minimum viable information, and we will gradually go through the wiki to fill the new documentation with relevant and updated content.

3. Project life

Governance

During a Gephi Week, there is always the need to discuss and improve the project’s life. This year’s focus was on governance.

We had the help of Celya Gruson-Daniel to accompany us in the process of formalizing how we function as a collective, and become better at onboarding new members.

Part of this process will be to integrate the project’s life more firmly into the Open Collective platform, and facilitate donations through the platform. This will make the project more transparent and easier to manage.

▲ Discussing Gephi governance, finances and community with Celya Gruson-Daniel. Photos: Matthieu Totet

Documenting the project in video

Like the Paris 2022 edition, we had the chance to have Nicolas “Datalgo” Bouchaib with us. We were able to have live streams every day to talk about data science and network analysis in French and English, and provide insights into the project in video.