Building an App with Gen-AI: Lessons from a Product Manager

It's getting hot in Bern - and we are back with a spontaneous ProductTank that you will benefit from both as product people and in your leisure time :)

aaremarzili.info is a long-standing web app for checking the Aare river temperature, with roots going back to 2002.
When strong competition entered the market, David Wiedmer took over the platform and rebuilt it from scratch, investing around 100–200 hours. Despite solid traction, around 100'000 seasonal users and more than 500'000 requests, it became clear that competing at the same level would require significantly more time and resources.

Instead of building a native app, he chose a pragmatic path and developed a progressive web app. The project remained sustainable, even generating some revenue each season, leading to a decent balance overall, but over the years, usage only increased marginally. It worked, so he didn’t push it further.
That changed with the rise of Generative-AI.

In 2024 and 2025, David turned aaremarzili into his personal Gen-AI playground, but with real users and real production constraints.
In this talk, he’ll share:

• How he used AI to evolve an existing product
• How his skillset changed
• What worked and what didn’t
• Real User Feedback
• And what it really takes to bring an AI-supported product into production

This is a practical, honest journey. No hype, just real learnings from building and shipping.

Talk language
English