Demo — what you'll see in the app
Apple · Build Challenge · 42 School
'Retia': three students from 42 want to make online reading a little clearer
Born in forty-eight hours during a build challenge held at 42 School alongside Apple and the Cmd+F team, the Retia app slips right into the iOS share menu to help you, in a single tap, better understand what you are reading.
It is 3:12 a.m. in the heart of the 42 School “cluster” in Paris. The bluish screens cast long shadows on the concrete walls. It is here, between two cups of lukewarm coffee, that three students — Louis Betmalle, Tristan Allal-Rimbaud and Frédéric Becerril — put together, in under two days, a small app named Retia.
The idea fits in a single sentence. You are reading an article — this one, for instance. A concept escapes you, a claim feels shaky, a proper noun means nothing to you. Rather than opening five tabs, you tap the iOS Share button, you pick Retia from the list, and within seconds the app hands you the essentials: the thread of the piece, the related ideas and the keywords worth digging into — all without ever leaving the page.
“We didn't want yet another app to open. We wanted something that lives where people already read — inside the share menu.”— Louis Betmalle, co-founder of Retia
The idea comes from a slightly uncomfortable observation. “We read a huge amount, and we understand half as much as we think we do,” says Tristan Allal-Rimbaud. “Retia is mostly a way to stop lying to ourselves about it.” The trio then set out to build a share extension, that iOS mechanism which lets any app slot itself into the menu triggered by the share icon.
The project did not stop at the build challenge's forty-eight hours: the three friends keep refining it. Retia will land on the App Store in the coming weeks. In the meantime, its creators have just one piece of advice: open an article, tap Share, and let Retia do the rest.
AI can be wrong. Double-check anything that matters.
Context
To read this article properly, you need to know the setting. 42 School is a Paris coding school (founded in 2013 by Xavier Niel) known for its unusual model: free, with no teachers and no lectures, running on projects and peer-to-peer learning in a large open space called the cluster.
It is natural ground for build challenges — intensive creation sprints, close to hackathons, where you must ship a working product in a very short time (here, 48 hours). The article covers one of these sprints, co-organised with Apple, whose engineers came to coach the teams on one precise iOS building block: the share sheet. Any app can slot into it through a Share Extension, which lets you act on content without leaving the screen where you read it.
Finally, the name Cmd+F is a nod to the universal “find on page” keyboard shortcut — here, also the name of a team specialised in search and in connecting information, which provides the app's engine. Understanding these four elements (42 School, build challenge, share sheet, Cmd+F) is enough to grasp why and how Retia was born.
Synthesis
What this text tells is not just “three students build an app”: it is the meeting of a learning culture (42's, where you learn by building, fast and together) and a deliberately narrow technical constraint (a single feature, grafted into the iOS share sheet).
The 48-hour format is not a footnote: it is precisely what forces the product's philosophy. When Apple pushes the team to “do less but better”, it is the logical consequence of a short deadline and of a system extension that, by nature, must do one thing well. Rather than another app to open, Retia sits inside the gesture you already make — sharing — and leans on Cmd+F's connection engine to turn an opaque article into a clear reading thread.
The demo you are living through is the best proof of concept: an article about Retia, contextualised by Retia.
Article
'Retia': three students from 42 want to make online reading a little clearer
Born in forty-eight hours during a held at alongside and the team, the Retia app slips into the iOS share menu to help you, in a single tap, better understand what you are reading.
It is 3:12 a.m. in the heart of the 42 School in Paris. The bluish screens cast long shadows on the concrete walls. It is here, between two cups of lukewarm coffee, that three students put together, in under two days, a small app named Retia.
The idea fits in one sentence. You are reading an article — this one, for instance. Rather than opening five tabs, you tap Share, you pick Retia, and the app hands you the essentials in seconds — thanks to a , that iOS mechanism which slots into the share menu.
“They pushed us to do less, but better. A single action, flawless.” The result is deliberately minimal: a sheet sliding up from the bottom, a title, a clear path. No account, no ads.
The project keeps being refined: Retia will land on the in the coming weeks. Until then, one piece of advice: open an article, tap Share, and let Retia do the rest.
Keyword