EPSEELON

Software engineering is dead. Long live product engineering.

I coach teams through real AI adoption, and I build ambitious products with AI. One method for both: specifications before code, adversarial review before implementation, verification before delivery.

By Sébastien Arbogast, Product Engineer

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Portrait of Sébastien Arbogast in ink and ultramarine duotone
The transition

Twenty years of code. Two years of grief. Seven months that changed everything.

I wrote my first application as a teenager and never stopped. For fifteen years I built software for startups and small companies as a freelance consultant, handling everything from architecture to deployment, every line written by hand.

Two years ago the leads dried up. Clients started vibe coding their own prototypes, budgets evaporated, and the market stopped paying for clean, secure, scalable software. What followed was a real grief, denial and anger included.

Then I stopped fighting the wave and learned to ride it, on my own product first, where no client’s business was at risk. That is where the method was born, one gate at a time: specify, review, verify. The craft survived; it just moved up a level.

Then
Two or three client projects at a time, every line handwritten
Now
Skaoot, my own product, shipped solo and driven by specs, review gates, and AI
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Two doors, one method.

Adopt an AI

Coaching for teams whose AI adoption is stalling.

“Here are some tokens, go ahead” is not a strategy. Trust in AI cannot be forced, only experienced, task by task, with the right workflows at each level. I coach engineering teams and their leadership through that progression, and through the change management the tools alone will never do.

  • Progressive workflows that build trust incrementally, from boilerplate to full features
  • Context engineering: project memory, skills, and instrumentation that raise output quality
  • Team and role redesign, because AI adoption is an organizational change, not a license purchase
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Augmented Intelligence

Ambitious products, built with AI and powered by it.

The ideas that were never worth the effort suddenly are. I take software projects from idea to production the way I built Skaoot: specification-driven, security-conscious, built to evolve, with AI doing the heavy lifting and twenty years of engineering judgment driving it.

  • Full lifecycle ownership: analysis, architecture, build, deployment, operations
  • AI as a feature, not a chatbot: document understanding, data synthesis, generative interfaces
  • Software that survives real users: private, scalable, maintainable
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The proof runs in production.

Skaoot is my travel assistant for digital nomads, and my laboratory. I built it alone, end to end, with AI as both development tool and product capability: it reads unstructured booking emails in any language and turns them into a living itinerary. No chatbot in sight.

5 months
from first commit to v1, solo
7 months
to a second major release
1 person
no employees, no investors
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Skaoot itinerary screen: next up, online check-in for flight TK1942 from Brussels to Istanbul, then the travel day as a timeline: leave for the airport, check-in and bag drop, boarding, gate departure.
Skaoot booking screen: a one-way Emirates flight from Denpasar to Cape Town, with booking code, baggage allowance, and each leg with its seat, gate and terminal.
Skaoot for iOS: the living itinerary, and a booking read from an email. Real screen captures; only the phone outline is drawn.

The proof has a witness.

Portrait of Davy Taccogna in ink and ultramarine duotone

Davy Taccogna

Co-founder of Scorelyr, opens in a new tab

Davy Taccogna and his co-founder hired me in 2023 to build Scorelyr, their music app, before large language models were part of my toolkit: I wrote it from scratch, by hand. This year I moved our work together to fully AI-driven development, one gate at a time. Same client, same product, two eras. Here is what it looks like from his side.

2023
Scorelyr, written from scratch by hand, without any LLM
2026
Same product, same client, fully AI-driven development

We have been working with Sébastien on Scorelyr for several years. What I particularly appreciate about him is that he always listens and is ready to look for a solution when a problem comes up. He does not just build what we ask for: he tries to understand our needs and the reality of the product in the field.

Since he integrated artificial intelligence more deeply into the way he works, we have clearly seen Scorelyr’s development accelerate. We have been able to solve sometimes complex problems much faster, evolve certain features, and even replace, in very little time, important technologies the application relies on.

Today Sébastien knows our product very well and knows how to turn our ideas and needs into concrete solutions. That availability, that ability to find solutions, and that commitment to the project are what I value most in our collaboration.

Translated from the French.

Your transition has a method.

If your team’s AI adoption is stalling, or an ambitious product idea just became feasible, let’s talk about what the method looks like in your context.

Book a call, opens in a new tab sebastien.arbogast@epseelon.com

Working remotely, worldwide.