Free SEO and GEO Tools
I build free SEO tools, open source, so anyone can audit their website and measure their visibility in AI answers without a subscription. The code is public on GitHub.
Arachnide SEO Spider, the free SEO crawler
Arachnide is an open-source SEO crawler designed as a free alternative to Screaming Frog. It crawls your website the way a search engine would and lists everything that holds back its search performance.
- Crawls over a million pages, with or without JavaScript rendering.
- Compares raw HTML and rendered HTML: content, links, canonical and H1 changed by JavaScript.
- Titles, meta descriptions, canonicals, hreflang, robots directives, structured data, Open Graph.
- AI crawler access (GPTBot, ClaudeBot, PerplexityBot…) and llms.txt file detection.
- Keyword cannibalization, thin content, orphan pages.
- Server log analysis, Google Search Console and GA4 connections.
- Prioritized issue report, with how to fix each issue, and PDF export.
- Interface in six languages: French, English, Spanish, German, Italian and Portuguese.
I used Arachnide to audit this site before rebuilding it on Éclair CMS: thin content, cannibalization, images in older formats and layout shifts were listed, then fixed.
Vigie, the AI visibility tracker
Vigie is an open-source AI visibility tracker (MIT license) that runs on your own computer. It asks ChatGPT, Claude, Gemini and Perplexity your customers' questions, then measures how often your brand is cited, how it ranks against your competitors (share of voice) and which sites the answers rely on. No account, no subscription: you use your own API keys and your data stays with you. It's the tool I use for the monthly tracking in AI search optimization.
Why free SEO tools?
Because professional SEO tools often cost several hundred euros a year, while small businesses need them just as much as large ones. Publishing them as open source also lets me improve them with feedback from the SEO community. If you'd rather delegate, the GEO audit uses these same tools.
Frequently asked questions about the tools
Is Arachnide really free?
Yes. It is free and open source: its code is available on GitHub.
Do I need to know how to code to use Arachnide?
No. The GitHub repository explains the installation step by step, and the interface is available in six languages.
Can I report a problem or suggest an improvement?
Yes, by opening an issue in the tool's GitHub repository.
Have you built other software?
Yes, Éclair CMS, a database-free CMS with SEO and GEO built in. All my projects are on the Work page.