Paste a robots.txt (or fetch one from a live domain) and test whether a path is allowed or blocked for a given user-agent — using the same most-specific-group and longest-match-wins rules search engines follow. Parsing and matching run entirely in your browser; fetching a live domain's robots.txt is the one part that has to go through this server.
curl -sS -X POST https://devops.majbase.com/robots-txt-tester/api -H "Content-Type: application/json" \
-d '{"robots_txt":"User-agent: *\nDisallow: /admin/","user_agent":"Googlebot","path":"/admin/page"}'Returns {"groups", "sitemaps", "allowed", "matched_rule", "matched_user_agent"}, or {"error": "..."}.