Budd app for a stigma-sensitive subject

Background

The Institute of Tropical Medicine has been supporting men who engage in chemsex on a medical and psychological level for many years. In day-to-day practice, researchers and clinicians identified a concrete need: reliable, scientifically grounded information was difficult to find, and a low-threshold tool for those directly involved was entirely absent.

The ITG asked us to translate that need into a digital product, one that not only informs, but also guides and empowers, with respect for every user's privacy and autonomy.

Challenge

A stigma-sensitive subject, a broad audience
Chemsex carries social stigma. The app needed to be non-judgmental whilst delivering clear health information for both newcomers and experienced users.

Privacy as a fundamental requirement
Extensive user research revealed that privacy and anonymity are crucial. The app could not have a social function and had to be safe to use on shared devices, including during events.

Scientific foundation, human tone
All content is the result of a rigorous co-development process with the ITG, the University of Antwerp, Sensoa and VAD. The information needed to be accurate and accessible  without being patronising.

Maximum reach, zero installation barrier
A native app via a store is visible in your download history and can reinforce stigmatisation. Budd had to function as a progressive web app: installable via the browser, without a store, without leaving a trace.

Solution

A buddy. Not an app. No judgement.
Budd is a progressive web app, available at app.budd.be on desktop, tablet and mobile. No download required, no visible icon in an app store. Anyone who wishes to can add the app as an icon to their home screen as discreetly or as visibly as the user themselves chooses.

The name says it all: Budd is a buddy. Not a clinical tool, not a moralising one. The app supports users at their own pace, in their own language in Dutch, French and English.

Users can use the app completely anonymously for the information section. Those who create an account unlock the personal tools: calendar, diary, dashboard. No data is shared with other users.

Support in three phases

Before — Preparing mindfully
Schedule events in a personal calendar. The preparation tool helps you reflect on your intentions and personal boundaries. A handy checklist ensures you don't forget anything. The combination tool shows which chemical combinations carry risks.

During — Staying alert and informed
Step-by-step guides for potential emergency situations. Direct access to emergency numbers. A timestamped notebook to keep track of what was taken and when.

After — Reflecting and growing
A mood diary to process feelings and experiences. A personal dashboard with an overview of participation and state of mind over time. And a full overview of available support services for those who wish to go further.

Impact

Budd was featured in 2026 at the Darklands Festival in Antwerp — Europe's largest fetish festival, with 27,000 visitors. As part of the ITG's Kink Responsibly project, visitors on site were given access to the combination tool via a touchscreen, and could experience how it enables them to make considered choices to reduce risks.

The project demonstrates that a digital product can be more than a screen: it became a bridge between the community, researchers and care providers.