Agency first, then product.
I’m Jonathan, John for most people. I’m a French growth advisor and SaaS builder, and I have spent more than ten years on SEO, growth and the tech that makes both scale.
I studied marketing, then went to a coding bootcamp in 2015 because I wanted to build the things I was recommending. For eleven years I was co-founder of Deux.io, a growth agency that worked with more than 500 companies, among them Luko, MeilleursAgents, Legalstart, HEC and Axa. 73% of those clients came through recommendations. I exited in January 2025.
Along the way I co-founded Derrick, with one day a week at first. It began as a Google Sheets add-on for importing and enriching LinkedIn data. It now has more than 31,000 users, a web app, an API and an MCP server.
What ties it together is a preference for systems over campaigns. Automate what brings no value, and let people focus where they have the most impact. Growth Mindset is where I now do that with other founders, and where I write down how.
The path so far.
- 2009-2014
Marketing studies, from Aix to Brazil
A DUT at Aix-Marseille University, a master’s at Institut Mines-Télécom Business School, and a semester at PUC Paraná.
- 2013
Project manager at Orange Horizons
Business development for mobile virtual operators outside Orange’s footprint, in a very international team.
- 2014
Co-founder of Deux.io
A growth agency that doubled as a playground to test methods, tools and tactics.
- 2015
I learn to code at Le Wagon
Nine weeks of algorithms, SQL, JavaScript and Ruby on Rails.
- 2016
Growth Mindset and training
I start advising startups under this name, while Deux.io launches a growth training program that has since trained more than 500 people.
- 2018
LaGrowthMachine comes out of Deux.io
A multichannel prospecting tool, with more than 10,000 users today.
- Oct. 2022
I co-found Derrick
A Google Sheets add-on, built on the side, one day a week at first.
- Jan. 2025
Exit from Deux.io
After 11 years and more than 500 clients, I go back to working independently as Growth Mindset.
- 2026
Derrick passes 31,000 users
Now much more than a Sheets add-on, with a web app, an API and an MCP server.
What I do today.
Go-to-market
Growth strategies to launch a product or service.
Growth audit
A clear, actionable roadmap to break through a ceiling.
TAM
Understand, size and win your target market.
SEO and CRO
Bring UX, SEO and conversion together.
Enrichment and automation
Turn raw data into concrete, scalable opportunities.
What they said.
Jonathan est très réactif et a su développer des compétences techniques poussées pour mettre en place des méthodes de growth hacking. Au fil du temps, il a su étendre son périmètre de l’opérationnel à la stratégie pour nous accompagner dans notre croissance.
Très à l’écoute et autonome, Jonathan a su rapidement monter en compétence sur les sujets mobiles, MVNO en particulier, tant sur les aspects business que techniques, le tout dans un contexte très international. Son esprit créatif et son enthousiasme ont été de réels atouts à l’équipe.
How I work.
Creativity
The best channel is often the one your competitors have not thought about yet.
Automation
If I do something twice by hand, I start looking for the way to never do it again.
Scalable systems
Effort should compound. A good system is still paying off two years later.
