The best online tools to learn everything about a website

How can I contact the website owner? Where is a particular website hosted? What other websites are hosted on the same server? Is the site using WordPress or Gatsby? Which ad networks do you use to monetize a site? Is my site accessible from China?

Here are some very useful online tools that will help you know every detail of any website.

See also: Essential Tools for Programmers

just-ping.com — Use Just Ping to find out if a specific website is accessible from other countries. Ping has tracking servers all over the world, including Turkey, Egypt, and China, so if the ping results say 100% packet loss, the site is unreachable from that region.
who is — If you want to know the website owner’s address, email, and phone number, this free Weiss lookup service can help. This is a universal search service, which means it can query the Wis database of all popular domain registrars at once.
whoishostingthis.com — Enter the URL of any website and this online service will show you the name of the company where the website is hosted. This can be useful if you need the web hosting provider’s address to write a DMCA notice, or if you want to change web hosts.
chillingeffects.org — When there is a copyright complaint against a website, a copy of that letter is stored in the Chilling Effects database. Anyone can query this public database to find out about copyright infringement complaints on a particular website.
myip.ms — MyIP.ms provides a comprehensive report of any website or IP address. You can find out about the hosting provider, physical location of the website, website IP address change history and DNS information. Netcraft It also provides similar reports.
reversewhois.com — Reverse Wis search helps you determine other people’s websites. You can search the Wis database by email address or domain name.
Developed by .com – Use BuiltWith to discover the technology stack of any website. It helps you find out the domain’s mail service provider, advertising partners, tracking widgets installed on the website and whether the site is using a CDN like Amazon S3 or Google Cloud. See example.
ssllabs.com – The certificate checking tool verifies your site’s SSL certificate and ensures that it is properly installed, trusted and does not display errors to any visitors to your site.
semrush.com – This is the go-to tool if you want to analyze your competitor’s website. SEM Rush helps you find out what organic keywords people are using to find a website, what the site’s traffic is, and which competing websites are.
dnsmap.io – When you buy a new domain or change from one host to another, the DNS records for the domain will change and it may take time for these changes to propagate worldwide. The tool checks DNS records from different geographic locations and can verify your domain’s A, CNAME, TXT, and MX records. whatsmydns.net It is also a good option.
toolbox.googleapps.com – If there are e-mail messages, including those sent by e-mail Letter mergeIf you don’t access your domain’s recipient mailbox, use this Google tool to make sure DMARC, DKIM, and SPF records are set up correctly for your domain.
browserstack.com – View your website’s responsive design on multiple desktops, tablets, iOS and Android phones running different OS versions.
screenshot.guru – If a website is inaccessible, use Screenshot Guru hosted on Google Cloud to check whether the website is down or not.
thinkwithgoogle.com – Google’s mobile speed tool helps you find out how fast your web pages load on mobile phones over 3G and 4G networks. You can also compare your mobile speed with other websites.
testmysite.io – A simple site testing tool from Netlify that measures and ranks your site’s load time from different regions around the world.
developers.google.com – Get the page speed score of any website on both desktop and mobile devices. The higher this number, the better. The Google Tool provides recommendations on how to improve results.
httparchive.org — An HTTP archive is a repository of all performance-related metrics for a website. It records the size of pages, their average load time and failed requests (missing resources) over time.
Website Monitoring – Use this Google Sheets-based website monitoring tool to get alerts when your domain is down or inaccessible.
Flush the DNS – Use this tool to clear the Google DNS cache for a domain. If you’ve changed DNS servers for your domain, changing registrars or DNS hosting in the past few days, clear your primary domain name first before dumping any subdomains. OpenDNS has it too Web tool To refresh the DNS cache.
DomainTools – The tool monitors one or more web domains and sends email alerts when the domain expires, the domain is renewed, name servers are changed, or the registrant information for the domain is updated.