42 · The network
42 is why I think the way I think.
No teachers. No tuition. No grades. 26 days of sink-or-swim to get in, then three to five years of peer-reviewed projects. I went through 42 Paris and then helped launch 42 Lisboa as part of the founding dev team. This page is the inside view — what 42 actually is, how it got built, and why it still produces some of the most shipping-minded engineers in Europe.
The premise
Four things it removed on purpose.
42 exists because Xavier Niel thought traditional tech education was built around the wrong constraints. In 2013 he opened École 42 in Paris with a short list of things deliberately not included:
No teachers
Nobody stands at a whiteboard. Nobody grades you. You learn by doing, peer-reviewed by the students one desk over.
No tuition
Fully free. Xavier Niel funds it privately. The point is access, not gatekeeping. Your bank account is not the filter — your stamina is.
No lectures
Projects from day one. Specs arrive, deadlines land, you ship or you don't. Figuring out how is the curriculum.
No prerequisites
No degree, no age cap, no CV needed. A 17-year-old dropout and a 35-year-old pharmacist get the same door.
Origin
A French billionaire, an education problem, and a Douglas Adams reference.
Xavier Niel built Iliad — better known as Free, the mobile and internet carrier that cut French telecom prices in half. He has a long, public frustration with how France trains engineers: too theoretical, too expensive, too linear, and too allergic to failure. In 2013 he put a reported €70M of his own money into a new kind of school.
He paired with Nicolas Sadirac, Kwame Yamgnane, and Florian Bucher — the team that had been running Epitech, a private French tech school that was already pushing project-based teaching. Together they pushed the format further: remove teachers entirely, remove tuition, remove schedules, remove grades. Keep only the work.
The name is a joke with a serious subtext. In Douglas Adams' The Hitchhiker's Guide to the Galaxy, 42 is the answer a supercomputer gives to "the ultimate question of life, the universe, and everything." The punchline is that nobody ever figured out what the question was. The school's bet is similar: we can't tell you the answer to your career, but we can give you the environment to find it.
École 42 Paris opened in November 2013 with a handful of students. By 2016 it had a campus in Silicon Valley. By 2024 it had grown into a global network — the 42 Network — spanning more than fifty campuses across five continents.
Me — 42 Paris, student days
The program
How you actually get through it.
There is a structure — it just isn't a timetable. Four stages, each one filters a different thing.
- 01
The online test
Logic and memory puzzles. A few hours. Filters for pattern recognition, not knowledge. You either move to the Piscine or you don't.
- 02
La Piscine
26 days of full-immersion selection. Shell scripting, C, peer evaluations, exams every Friday. The campus is open 24/7 and people live on it. Roughly a third make the cut.
- 03
Common core
Eighteen months to two years of foundational projects. C, algorithms, data structures, networking, Unix, graphics, web. Each project is peer-evaluated before it counts.
- 04
Specialisation & internship
You branch: systems, AI, graphics, security, web. At least one real-world internship, usually longer. Some students finish in three years. Some take five. Both are fine.
The culture
What the building feels like at 3 AM.
Every 42 campus has a "cluster" — a glass-walled room filled with identical iMacs and hundreds of people ranging from fresh dropouts to 40-year-old career-switchers. The culture is written in how that room operates.
Build. Break. Fix.
You break the build. You fix the build. You break it again. The loop is the lesson — and it is relentless.
Peer-to-peer
You evaluate your classmates' work and they evaluate yours. You learn to defend a choice, to read someone else's code, to disagree without being a dick.
24/7 campus
The clusters never close. 4 AM debugging sessions, floor-naps between deadlines, pizza on the monitors. You meet people at their best and their worst.
Google is your friend
A line everyone learns in week one. The skill is not knowing — it is finding, filtering, and verifying. You walk out self-teaching for life.
“ 42 doesn't teach you to code. It teaches you how to learn to learn.
The network today
What a decade of this produced.
50+
Campuses
Across 30+ countries — Paris, Lyon, Lausanne, Lisboa, Madrid, Tokyo, Seoul, Berlin, São Paulo, and more.
Tens of thousands
Students
Active learners across the network at any given time. Alumni in the thousands, in every major tech hub.
Everywhere
Where they land
Google, Apple, Amazon, Stripe, Datadog, Doctolib, Criteo, ElevenLabs, Mistral, plus hundreds of founders shipping their own.
€0
Tuition paid
Privately funded by Xavier Niel. No debt. No strings. That alone disqualifies most of higher ed by comparison.
My 42
From a seat in Paris to a desk at 42 Lisboa.
I arrived at 42 Paris after quitting high school at 15, working a handful of manual jobs, and teaching myself code from YouTube and forums. The Piscine was the first environment that matched how I actually learn — no syllabus, no one telling me to slow down, and enough peers around me to pressure-test every bad habit I'd picked up alone.
After the Piscine I stayed and ran through the common core. I did my student internship on the 42 dev team, then joined 42 Network — the Paris-based organisation that builds the tooling used across every campus in the network: the intranet, the peer-review platform, the auth and billing stack, the internal tools staff use to run a school. When 42 Lisboa was greenlit in 2020, I was hired from France to join its founding crew — porting and extending that same infrastructure for a new country.
That experience — being an alum and a builder of the thing — is what this page is trying to translate. If you want the long version of my story, the about page has it in chapters.
Common questions
What people actually ask about 42.
Is 42 really free?
Yes. Tuition, campus access, tools, electricity — all zero. It is privately funded by Xavier Niel (founder of Iliad / Free). You pay for your own housing and food. Some campuses offer student housing at subsidised rates. There is no catch — Niel's stated reason is that he wants to widen the pipeline of tech talent in countries where it is bottlenecked by cost.
Does 42 give you a diploma?
42 is not a recognised university and does not issue state-accredited degrees in most countries. What you get is a validated curriculum on your profile, a body of work, and — more importantly — a hiring-signal that top tech companies have explicitly learned to read. In France, Portugal, Spain, and increasingly the US and Japan, 42 on a CV gets you a technical interview at serious companies.
Who founded 42 and why is it called 42?
Founded in 2013 in Paris by Xavier Niel, a French entrepreneur best known for founding Free (Iliad). His co-founders were Nicolas Sadirac, Kwame Yamgnane, and Florian Bucher, who previously ran Epitech. The name is a nod to Douglas Adams' Hitchhiker's Guide to the Galaxy — "42" is the answer to life, the universe, and everything.
What is the Piscine?
"Swimming pool" in French. It is a 26-day intensive selection — the only filter between you and the full curriculum. You live at the campus. You ship C projects every day. You peer-review each other's work on a strict grading system. Exams every Friday. Roughly one-third of participants earn a seat in the school. It is designed to be sink-or-swim by name and by nature.
How long does 42 take?
Officially 3 to 5 years. In practice it varies wildly — because there are no class schedules, no grades, and no forced pacing, you move at your own cadence. Some students finish the common core in 18 months while working a part-time job. Others take 4 years and specialise deeply. The curriculum has roughly 21 milestones organised as a skill tree.
Is it worth going to 42 vs a normal CS degree?
Different tools for different people. A CS degree gives you theory, credentials, and a linear calendar. 42 gives you a shipping habit, a peer network, zero debt, and a proof-of-work portfolio. If you already learn well on your own and a structured classroom makes you restless, 42 is probably the better fit. If you need the scaffolding of a syllabus and lectures, it is not. The two programs optimise for different shaped brains.
Where are the 42 campuses?
The 42 Network spans more than 50 campuses across 30+ countries — Europe, North and South America, Asia, the Middle East, North Africa. Notable campuses include 42 Paris (the flagship), 42 Lyon, 42 Lausanne, 42 Lisboa, 42 Madrid, 42 Berlin, 42 Wolfsburg, 42 Tokyo, 42 Seoul, 42 São Paulo, 42 Abu Dhabi, and 42 Heilbronn. The full, up-to-date list lives at 42.fr.
What is 42 Lisboa and what was your role there?
42 Lisboa is the Portuguese campus of the network, launched in 2020 with public and private backing in Lisbon. Before that I had done my student internship on the 42 dev team and then worked at 42 Network — the Paris-based organisation that builds the tooling used across every campus. When 42 Lisboa was greenlit I was hired from France to join the founding crew, porting that same infrastructure to a new country. The experience shaped a lot of how I approach launching software today: the difference between a great product and a great launch is almost never the code.
David Dacruz
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