Work

Before advising you, I apply my methods to my own work. Here are my main public projects: a CMS, two SEO tools, two websites and a series of books, all verifiable online, so a US prospect can judge the quality of my work before our first call.

Éclair CMS, the CMS built for Google and AI engines

The Éclair CMS editor with its SEO and GEO analysis, and a published article shown on a phone

I created Éclair CMS, an open-source PHP CMS with no database, designed for freelancers and small businesses. The archive weighs less than 900 KB, every page is served from a static cache, and SEO and GEO are built in without a single plugin: structured data, sitemap with hreflang, redirects, llms.txt, a Markdown version of every page and a live GEO score in the editor. This site runs on Éclair.

100/100 on all four Lighthouse scores and a time to first byte 1.6 times faster than WordPress with a caching plugin, according to public, reproducible benchmarks.
Built-in AI assistant (Claude or ChatGPT) and MCP connector: the AI writes drafts, nothing is published without your click.
WordPress migration without losing a URL with the free Eclair Export plugin: tested on 500 posts and 635 old URLs, zero 404 errors.

All the features of Éclair CMS

They all run on Éclair CMS: see the websites built with Éclair.

Arachnide SEO Spider

A free, open-source SEO crawler, an alternative to Screaming Frog. I designed, developed and published it on GitHub, and I keep improving it with feedback from the SEO community. The report used to prepare this site was produced with Arachnide. What Arachnide does · View on GitHub

Vigie

An open-source AI visibility tracker, released in October 2026: it measures a brand's presence in AI assistant answers, question by question. View Vigie on GitHub

DelfOnline

An online platform for DELF, DALF and TCF exam preparation. I designed it, developed it with AI tools, launched it and optimized it for search on my own. delfonline.es

GustinAI

A website and AI training offering for businesses, designed from the outset to be cited by AI engines, in French, Spanish and English. gustinai.com

La Bible de Claude AI

A reference guide to Claude AI and an Amazon best-seller, published in six languages: English, where it is titled The Claude AI Bible and sold on Amazon.com, as well as French, Spanish, German, Italian and Portuguese. View the book on Amazon

thierrygustin.com

This very website: moved from WordPress to Lovable, then to Éclair CMS, without losing a single URL (178 old URLs redirected in a single hop). Multilingual with reciprocal hreflang, including this US English edition, served from a static cache, cookie-free, with complete structured data, an llms.txt and a Markdown version of every page for AI engines. View its source code: it's all there.

What about client case studies?

I only publish verifiable results, with my clients' consent. I won't invent US case studies to look local: I'll show you concrete examples during our first video call.

Have a project in mind?

Let's talk about your website and what AI engines say about your business.

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