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Grégoire GuillotGG

Grégoire Guillot

Startup builder - AI, Product, Growth, Voice

€450/day
Paris, FR
3-7 years

Average response time: 4 hours

Freelancer profile translated to English.
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About Grégoire

I am a multi-skilled builder who helps startups transform an idea into a running system. A graduate of ENSTA Paris, HEC, and UC Berkeley, I combine technical rigor, speed of execution, and business understanding.

My playground:
- AI agents and AI in production
- Fast and solid full-stack development
- Voice AI (LiveKit, Vapi, Deepgram, OpenAI, etc.)
- B2C acquisition and growth tech
- Product and business workflow automation

I founded Prepstr, a company where I built the product, the technical structure, and several automation systems. I also developed a real product and business insight alongside technical execution.

Some benchmarks:
- 10,000+ users in the last 12 months
- 2+ million TikTok views in the last 3 months
- ~€20k in revenue generated 100% organically from TikTok in recent months
- Winner of the international hackathon EF x Lovable (May 2025)
- Winner of the Hugging Face x Zama hackathon (September 2024)

I work very well with early-stage teams that need someone fast, autonomous, and capable of bridging product, tech, and growth. I am particularly relevant for one-off or short-term missions.
  • French

    Native or bilingual

  • English

    Fluent

Can work on-site
Paris (up to 50km)

Experience

  • Prepstr
    Founder
    EDUCATION AND E-LEARNING
    October 2025 - Today (8 months)
    AI platform for preparing for TOEIC/TOEFL, with possible support from certified teachers.
    - Product development
    - Automation systems / autonomous agents
    - Organic B2C acquisition via TikTok and SEO: +1M views/month on TikTok via automated creatives across multiple accounts
    - ~€20k revenue
    Web Development Project Management Growth Hacking TikTok
  • WAVESTONE
    Consultant
    April 2023 - August 2023 (4 months)
    Paris, France
    • Data collection, visualization, analysis, and communication within a transformation project involving 100 people for a major player in the French railway industry; planning and leading decision-making and steering committees.
    • Conducted an internal study on the carbon footprint and decarbonization challenges for major retail players, as well as on technological tools and solutions for achieving carbon neutrality.
  • Pépite Start'up Ile-De-France
    Student Entrepreneur
    September 2022 - April 2023 (7 months)
    Paris, France
    Designed a social network connecting users in proximity via Bluetooth:
    ● Conducted a consumer study based on about a hundred participants
    ● Legal study on data processing (GDPR compliance, drafting of Terms of Service)
    ● Developed the solution (prototyping and design, UI creation); multi-channel communication strategy (landing page, social media, events); pitch competitions (Paris-Saclay, CentraleSupélec, Incuballiance)
    Designed a mathematics training for parents https://guide-mathematiques.super.site/
    ● Conducted about fifteen interviews to clarify needs
    ● Designed the value proposition and developed the solution (solution prototyping and design, creation of the online guide in 2 parts: technical video modules and methodology); developed a communication strategy.

Recommendations

FU
Nayel FeraiNF
Former user and 1 other person have recommended Grégoire

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Education

  • Postgraduate Entrepreneurship Track
    University of California, Berkeley
    2024
    L2L - Silicon Valley Innovation and Entrepreneurship Program
  • Master Spécialisé
    HEC Paris
    2024
    Entrepreneurship (X-HEC program)

Skill set

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