01We talk
A first conversation to understand what you want to build, your context and where you want to take it. No endless brief, we get straight to what matters.
Tech Partner in Paris
Your Tech Partner in Paris
I build business apps, SaaS and MVPs for Paris founders who want a real technical partner, not just another contractor.
A tech entrepreneur, not a task runner
I'm Valentin Muller, tech entrepreneur and founder of Aetherio. I build my own products and bring that same energy to my Paris clients' projects.
My work: turning your idea into a digital product that generates real value. Business apps, SaaS, MVPs. Technical strategy, architecture and development, end to end.
What sets me apart: all my clients keep working with me. I invest in your business for the long run, not just until delivery.
Based in Lyon, I work with Paris founders remotely and in person when needed. Distance isn't a constraint, it's a competitive advantage on pricing.
What I build for Paris companies
Digital products designed to generate results
01
High-performance websites
Custom-built sites optimized for conversion, SEO, and speed. Code, not templates.
From €2,500
02
Business apps & SaaS
Custom web applications that automate your processes and fuel your growth. Solid architecture, maintainable code.
From €5,000
03
MVP & Rapid prototyping
From idea to first user in weeks. Fast validation, short iterations, focus on what matters.
From €3,000
04
SEO & Performance
SEO and technical optimization built in from day one. Your product visible and fast from launch.
From €800
Why work with me from Paris?
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Projects delivered
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Satisfaction
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Years of experience
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Years of studies
Remote-first, in-person when needed
Video calls, Slack, shared tools daily. Travel to Paris for kickoffs, workshops and key moments. Best of both worlds.
Business vision
I think product, not just code. I understand your founder challenges because I face the same ones daily.
Competitive rates
Based in Lyon, my rates are 30-50% lower than Paris agencies, at equal or higher quality. AI lets me move even faster.
Business Vision
I don't code blindly. I think market, users, growth. Every technical decision serves your business.
Our latest work
SaaS apps, business tools, applications running in production and bringing in revenue. Each one solved a problem a founder could no longer carry alone.
Discover
Kabineo
SaaS Product / Co-foundedKabineo is the SaaS platform for running accounting firms, born from the bespoke Belho Xper tool and turned into a co-founded product, open to every firm.
Produit SaaSCofondateurMulti-tenantNestJS / Vue 3
Discover
Vijile
Desktop Application / Freelance ToolVijile is an automatic, 100% local time tracker for freelancers. It detects your active projects in real time, with zero manual input.
Application DesktopRust / Tauri100% LocalLanding Astro
Discover
Fideneo
Web Application / SaaSFideneo is an all-in-one cockpit designed to simplify and automate beauty salon management.
SaaSUX/UIWeb AppCRM
They trusted us
Founders and business owners who had a project, a need, a deadline. Here's what they have to say.
"Disponibilité, réactivité et implication. Valentin est professionnel et pédagogue."
A
Alban B.
CEO Belho Xper
"Il allie une expertise technique pointue à une solide vision business."
C
Charley A.
Co-fondateur Avnear
"Nous avons travaillé ensemble sur la conception d'une automatisation IA pour un E-commerce. Le suivi a été régulier, clair et efficace. Les délais respectés et le résultat impressionnant."
C
Chihab A.
CEO E-commerce
"Valentin a su être à l'écoute de mes besoins et les retranscrires dans une application de gestion de clientèle. Les résultats ont été plus que satisfaisants et de haute qualité."
S
Sandrine V.
Gérante Sandrin's Nail
"Une entreprise qui sait s'adapter parfaitement au besoin client."
S
Stanislas M.
Commercial
"Le site est clair, rapide, et nous permet de mettre en avant nos services de manière professionnelle. Nette augmentation des demandes."
C
Christophe R.
PDG Ravi Groupe
How we come on board your product
From the first conversation to a product that truly runs in production. A clear process where we act as your product team, not a vendor who ships and vanishes.
01/06
01
02Scoping and strategy
We define the scope, priorities and timeline together. We'll challenge your choices when needed: the goal is the right product, not just a spec that got built.
03Mockups and validation
We design your product and its flow as mockups. You approve everything before we write a line of code, zero surprises down the line.
04Iterative development
We build in functional blocks and you test as we go. We adjust continuously, with regular updates. Never a three-month tunnel with no visibility.
05Production deployment
Deployment, performance, monitoring. Your product goes into production, ready to hold up under load and actually get used, not just to exist.
06We stay on board
Launch isn't the end, it's the start. We watch the real numbers, fix what breaks, and add the features that actually matter. Your product keeps moving forward, and so do we.
Frequently asked questions
Vous êtes basé à Lyon, comment travaillez-vous avec des clients parisiens ?
La majorité de mes clients parisiens travaillent avec moi à distance : visio, Slack, outils partagés. Je me déplace à Paris quand le projet le nécessite (kickoff, ateliers stratégiques). Le résultat est le même, la proximité géographique n'est pas un frein.
Combien coûte une application sur mesure ?
Un MVP démarre autour de 5 000 €, une application métier complète entre 10 000 € et 30 000 €. Mes tarifs sont compétitifs par rapport aux agences parisiennes, à qualité égale ou supérieure. On cadre le budget dès le premier échange.
En combien de temps mon produit sera en ligne ?
Un MVP peut être en production en 4 à 8 semaines. Une application métier complète entre 2 et 4 mois. Vous voyez des versions intermédiaires chaque semaine.
Pourquoi un freelance plutôt qu'une agence parisienne ?
Pas d'intermédiaire, pas de commercial, pas de chef de projet qui fait écran. Vous parlez directement avec celui qui conçoit et code votre produit. C'est plus rapide, plus transparent, et souvent 30 à 50% moins cher qu'une agence parisienne.
Et si j'ai juste une idée, pas encore de cahier des charges ?
C'est le cas de la plupart de mes clients. On part de votre idée et on construit le cadrage ensemble. C'est justement mon rôle de transformer une vision en plan d'action technique concret.
Discover my resources
Technical Audit Checklist for Vibe-Coded Projects (Lovable, Bolt, Cursor)
Automate Vendor Management and Procurement with AI: The Complete Guide for Businesses
ROI of an AI Project After 6 Months: Key KPIs That Matter Once in Production
Automate Your Competitive Intelligence with AI: The Method and Tools for 2026
AI and Intellectual Property: Who Owns AI-Generated Code or Content?
The True Cost of AI in Production: Beyond the Advertised API Price
Have a project? Let's talk.
Free first call, no commitment. Let's see if we can move forward together.
Response within 24h
Free first call
Long-term commitment
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