Guillaume Gay is a software engineer building AI-powered tools and products. He founded MyTrainer and writes about LLM orchestration, evals and shipping AI features that hold up in production.
Areas of expertise
- LLM orchestration
- Evals
- Context management
- AI product engineering
Articles
- AI Fitness Coach Apps Existed Before ChatGPT: Why MyTrainer Is DifferentAI fitness coach apps are not new. The difference is that MyTrainer was built as an AI-native product around generative AI, with hyperpersonalized onboarding, context-aware support, and actions that happen in real time.
- Why MyTrainer Is More Than a GPT WrapperThe term GPT wrapper missed the point. The real value in products like MyTrainer is not training a foundation model from scratch. It is orchestrating the best models into a useful end-to-end fitness agent.
- Is AI relevant to use for coaching ?When I started MyTrainer, the main question was simple: is AI relevant for coaching? The answer became obvious through three lenses: availability, affordability, and quality.
- How MyTrainer AI was built - From a Zapier workflow to an Agentic AI AppThe origin story of MyTrainer AI — how a 2023 Framer landing page and a Zapier workflow turned into a fully agentic AI personal trainer app with 1,000+ monthly users in 2026.