{"version":"1.0","provider_name":"Lukas Wojcik - Blog","provider_url":"https:\/\/www.lukaswojcik.com\/blog","author_name":"luky","author_url":"https:\/\/www.lukaswojcik.com\/blog\/author\/luky\/","title":"Domain RDAP & Certificate Transparency Lookup: Registrar, Expiry, Forgotten Subdomains - Lukas Wojcik - Blog","type":"rich","width":600,"height":338,"html":"<blockquote class=\"wp-embedded-content\" data-secret=\"PBSRqY5nTT\"><a href=\"https:\/\/www.lukaswojcik.com\/blog\/en\/toolbox\/domain-rdap-certificate-transparency-subdomain-lookup\/\">Domain RDAP &#038; Certificate Transparency Lookup: Registrar, Expiry, Forgotten Subdomains<\/a><\/blockquote><iframe sandbox=\"allow-scripts\" security=\"restricted\" src=\"https:\/\/www.lukaswojcik.com\/blog\/en\/toolbox\/domain-rdap-certificate-transparency-subdomain-lookup\/embed\/#?secret=PBSRqY5nTT\" width=\"600\" height=\"338\" title=\"&#8220;Domain RDAP &#038; Certificate Transparency Lookup: Registrar, Expiry, Forgotten Subdomains&#8221; &#8212; Lukas Wojcik - Blog\" data-secret=\"PBSRqY5nTT\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\" class=\"wp-embedded-content\"><\/iframe><script>\n\/*! This file is auto-generated *\/\n!function(d,l){\"use strict\";l.querySelector&&d.addEventListener&&\"undefined\"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!\/[^a-zA-Z0-9]\/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret=\"'+t.secret+'\"]'),o=l.querySelectorAll('blockquote[data-secret=\"'+t.secret+'\"]'),c=new RegExp(\"^https?:$\",\"i\"),i=0;i<o.length;i++)o[i].style.display=\"none\";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute(\"style\"),\"height\"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):\"link\"===t.message&&(r=new URL(s.getAttribute(\"src\")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener(\"message\",d.wp.receiveEmbedMessage,!1),l.addEventListener(\"DOMContentLoaded\",function(){for(var e,t,s=l.querySelectorAll(\"iframe.wp-embedded-content\"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute(\"data-secret\"))||(t=Math.random().toString(36).substring(2,12),e.src+=\"#?secret=\"+t,e.setAttribute(\"data-secret\",t)),e.contentWindow.postMessage({message:\"ready\",secret:t},\"*\")},!1)))}(window,document);\n\/\/# sourceURL=https:\/\/www.lukaswojcik.com\/blog\/wp-includes\/js\/wp-embed.min.js\n<\/script>\n","description":"Asks the registry via RDAP who a domain is registered with, when it was created and when it expires, which status locks apply, which nameservers serve it and whether DNSSEC is delegated, then reads Certificate Transparency logs for every host name a certificate was ever issued for, including subdomains nobody remembers.","thumbnail_url":"https:\/\/www.lukaswojcik.com\/blog\/wp-content\/uploads\/2026\/08\/og-default.jpg","thumbnail_width":1200,"thumbnail_height":630}