How llms.txt made ChatGPT my #1 traffic source (a free IP API, 8 weeks in) Tags: webdev, seo, ai, cloudflare

I run HackMyIP , a free IP/privacy toolkit: IP lookup, VPN/proxy and DNS-leak detection, email-breach check, WHOIS, a CIDR calculator, and a free no-key API. It's about 8 weeks old. I'm writing this up because one decision moved the needle more than any backlink or keyword I chased: I made the site readable by AI assistants, not just by Google. Here's the part that surprised me. Looking at the last 28 days of analytics: chatgpt.com referrals: 157 sessions (107 of them engaged) Google search: 44 sessions That's roughly 3.5x more real traffic from ChatGPT than from Google. For a small, young site with thin domain authority, that ratio is not what I expected, and it's almost entirely because of a few small files most SEO guides never mention. What I actually shipped Three AEO ("Answer Engine Optimization") surfaces, all static, all boring to build: /llms.txt — a markdown index of the site written for an LLM: a one-line summary, the questions the site answers, and a categorized list of every tool with a one-line description and URL. Think of it as a sitemap that reads like documentation instead of XML. /llms-full.txt — the expanded version with more detail per tool, for assistants that will read a longer file. An OpenAPI 3.1 spec + an ai-plugin.json manifest under /.well-known/ , so an assistant (or a plugin runtime) can discover the API and the exact endpoints programmatically. The API itself is the thing those files point at: 10 endpoints, no key, no signup, JSON responses, CORS enabled ( Access-Control-Allow-Origin: * ). For example, GET /api/ip returns your IP plus geolocation, ASN/ISP, and a privacy classification: { "success" : true , "data" : { "ip" : "…" , "location" : { "city" : "…" , "region" : "…" , "country" : "…" , "timezone" : "…" }, "network" : { "asn" : 3462 , "isp" : "…" , "tls_version" : "TLSv1.3" }, "privacy" : { "type" : "residential" , "score" : 90 , "grade" : "A" , "is_vpn" : false , "is_datacenter" : false } } } Why this works (my best read of it)