Visual Inbox is a personal project I built during the 2025 winter break for a very simple reason: I wanted it for myself.
For a long time I wanted a way to step back and see how I was investing my attention in others. Not as a stack of messages, but as a network. Who do I bring into my network and who stays in the periphery? Which relationships are steady? Which ones fade? Email and calendars contain an interesting map of our social lives, but most interfaces never let you see the map. Visual Inbox is designed to bring that map to the surface.
This is not the first time I work on a related idea. While I was at MIT, I worked on tools focused on email visualization and social networks—most notably Immersion and Open Teams. Those projects were released as open source and have public GitHub repositories. But they were also hard to maintain and heavy to load.
So I decided to restart from scratch. From the raw need I had.
Visual Inbox is a new, independent build. I did not reuse code from those earlier projects, and this is not a continuation of them. I built Visual Inbox because I missed having that kind of view after Immersion and Open Teams were no longer online. MIT, nor any other academic institution, is affiliated with Visual Inbox (I built this on my own time during the winter break).
Visual Inbox was also a way for me to experiment in building software with AI. Traditionally, I have worked as the lead product designer and vision holder in teams I manage. This time, I wanted to explore the potential of doing something using AI as my only teammate. For this project, I used Gemini Pro extensively as a coding assistant, and I learned a lot during that process. I learned that building software with AI is not unlike building software with a small team.
As the vision holder, you don't try to one shot the project directly to the finish line. You build it gradually. I started with an app that just retrieved emails using OAuth. Then, I added a network visualization. Then, I started adding features, from the colors of the nodes to different UI elements. Then I started to refine the metrics. It was a highly iterative process, but one that is extremely rewarding. Updates that would take weeks, were completed in minutes. As a product designer, the compressed distance between an idea and a working tool is magical. It felt like playing Civilization as a teen: you always wanted to do one more turn.
Visual Inbox is not a research project, and it is not affiliated with any university, lab, or grant. I developed it independently, on my own time, as a personal build. But I think you might enjoy it too. It does not involve participants, recruitment, experimental interventions, or data collection for scientific publication. It is simply a piece of software that you may choose to use for your own personal insight.
Email inbox and calendar data are deeply personal, so I built Visual Inbox with a strict privacy posture: your email and calendar content is not sent to my servers. Instead, it is processed and stored locally in your browser (in the browser’s IndexedDB), so the visualizations are generated on your machine.
In simple terms: I send the application code to your browser, your browser talks to Google to retrieve the data you authorize, and the analysis happens locally. My server is not a pipeline for your inbox.
This privacy-first design is also interesting from an engineering perspective, since it makes the app extremely light to serve (everything is in your machine and the only thing my server does is send you a file with about 50kbs of code). I’m not interested in selling, sharing, or advertising on top of anyone’s personal data. I am just interested in helping people explore their own lives in the same browser they already use to access their email and calendar, by providing a different view.
I’ve spent much of my career thinking about networks and collective behavior, but Visual Inbox didn’t come out of a lab meeting or a grant proposal. It came out of a personal itch and frustration: I wanted a way to see the shape of my own communication. Am I too focused on people outside my team, inside my team? Are there gaps I am not seeing? Visualizations have for a long time been a way for me to reflect. I hope that if you try it too it helps you reflect about your life as well.
— César A. Hidalgo (January 4, 2026)
Visual Inbox is an independent personal project and is not affiliated with MIT, Google, or any other institution mentioned here. References to prior projects and product names are for historical context and identification only.