The free technical SEO crawler that also fixes what it finds
Arachnide crawls a website like Googlebot, scores it, lists every problem with its fix, and lets Claude or ChatGPT propose corrections that you approve and apply to your CMS. Open source, MIT, 100 % on your machine.
- Free and open source (MIT)
- No account, no cloud: data stays on your computer
- macOS, Windows, Linux · Node.js 18.17+
- Interface in 6 languages
What you get after a crawl
Everything a technical audit needs
About 95 checks in 14 families, the same analyses you expect from a desktop crawler, plus the things a crawler alone cannot do.
Audit and health score
Score out of 100 with an A–F grade, four pillars (technical, content, internal linking, performance), SEO issues page and a prioritised action plan with quick wins.
Fix in 1 click
Claude or ChatGPT write titles, descriptions, H1 and alt texts from the real page. You review before / after, approve, and a connector applies the change to WordPress, Shopify, Webflow, static files and more. Every change can be undone.
Site map in 2D and 3D
Classic Screaming Frog-style tree for reports, plus an exploration view: crawl tree, directories, internal link graph, filters, inspector and PNG export.
Segments
Audit a big site section by section: rules on 20 fields, first match wins, one click to create one segment per directory, score and statistics per segment.
Google data
PageSpeed Insights and Core Web Vitals, Search Console (API or CSV) and Google Analytics 4 to find orphan pages that still get traffic. Scheduled crawls with e-mail alerts.
AI agents and GEO
25 tools over MCP (Claude Desktop, Claude Code, claude.ai) and REST + OpenAPI 3.1 (ChatGPT Actions, LangChain, n8n, Make), a GEO readiness score and access checks for AI crawlers.
Fix in 1 click with Claude or ChatGPT
After a crawl, the Fix tab groups issues by impact and tags them AI-fixable, automatic or manual. The AI never touches your site by itself: it proposes, you approve, a connector applies, Arachnide re-crawls to verify.
- Fix one URL or “Fix all” for an issue type. The AI writes in the page’s language, from the page’s real content; redirects, canonicals and accidental noindex are computed without AI.
- Review before / after side by side, with a character counter, inline edit, approve, regenerate or ignore.
- Apply through a connector: WordPress, Drupal, Joomla, PrestaShop, Shopify, Webflow, Wix, files (static sites, _redirects, .htaccess, nginx, vercel.json), Cloudflare Worker, or manual instructions. Simulation mode is on by default.
- Each fixed URL is re-crawled and verified; the history lets you undo one fix or a whole batch.
Plug your own AI agent into Arachnide
Arachnide becomes the eyes and hands of your SEO / GEO agent. The agent reads the audit you have open, starts crawls that appear live in the app, explores pages, gets the prioritised action plan and the GEO readiness score, and fixes the site with your approval.
- MCP over stdio for Claude Desktop and Claude Code; MCP over HTTP for claude.ai custom connectors and hosted agents.
- REST + OpenAPI 3.1 for ChatGPT Actions, LangChain, n8n, Make or curl.
- A local access token, a rate limit, a log of the latest calls in the app, and write tools that go through preview, approval, journal and rollback.
- List and sitemap modes for agents since 3.21: crawl exactly the URLs they give you.
Measured, not promised
The 200 000-page figure comes from a local synthetic site crawled with “npm run bench -- --pages 200000” (3.21): crawl and analysis in 2,086 s, about 96 pages per second, saved in 38 s to a 62.5 MB file, peak memory 2.7 GB. The default budget is 500 pages; raise it in the options. Documentation →
Responsible use
Only crawl websites you own or are allowed to audit. On client websites, keep 2 to 5 simultaneous requests and add a pause on shared hosting. The interface listens only on your computer (127.0.0.1).
Free, open source, built in the open
Arachnide is published under the MIT license by Thierry Gustin, a freelance SEO consultant in Madrid, who built it for his own audits. Bug reports, ideas and pull requests are welcome. If Arachnide saves you time, a star on GitHub helps a lot.