Every public website hands its visitors a surprising amount of information about how it's built. Not secrets, just the normal things a browser needs to load the page. If you know where to look, you can tell the CMS, the framework, the CDN, the analytics setup and even who handles the domain's email, without logging in to anything.

Here's where that information lives. After that, two free tools we built that read it for you.

1. Response headers

server, x-powered-by, via, cf-ray and similar headers often name the web server, the language or the CDN. A cf-ray header means Cloudflare is in front. x-powered-by: PHP/8.x gives away the backend. Plenty of sites strip these, which is good practice, but many don't.

2. The HTML and the scripts it loads

Meta generator tags (<meta name="generator" content="WordPress 6.x">), asset paths (/wp-content/, cdn.shopify.com, assets.website-files.com) and global variables (window.Shopify, __NEXT_DATA__) are strong fingerprints. Third-party script URLs give away analytics, tag managers, pixels and chat widgets.

3. DNS

MX records tell you the email provider (Google Workspace, Microsoft 365, Zoho...). TXT records hold SPF and DMARC. Those decide whether the domain's email lands in inboxes or in spam, and a surprising number of small business domains have neither.

4. The TLS certificate

Who issued it and when it expires. An expired certificate is one of the most common "why is my site broken?" causes, and it's completely preventable.

Tool 1: Tech Inspector

We wrapped all of this into a free checker. Paste an address and it reports:

  • CMS and frameworks, with versions where the site shows them
  • analytics and marketing tags
  • hosting and CDN
  • the email provider, plus SPF and DMARC
  • the SSL details

It recognizes 7,600+ technologies and gives each detection a confidence level, because fingerprints can be ambiguous. You can download the result as a PDF, which we use when scoping a rebuild or explaining to a client what their site actually runs on.

👉 Tech Inspector

Tool 2: Uptime Monitor

Knowing what a site runs on is one half. Knowing when it stops running is the other. Small business sites usually go down for boring reasons: a hosting hiccup, a plugin update, a certificate or domain that didn't renew. And the owner tends to be the last to find out, often from a customer.

So we also built a free uptime monitor:

  • It loads your page every 5 minutes.
  • After two failed checks in a row it sends one email or SMS, then one more when the site is back. No flood of alerts.
  • It warns you 14 days before your SSL certificate expires.
  • An optional keyword check catches the "page loads but shows an error" case that plain ping checks miss.
  • Response-time history and an incident log come with it.

The free plan covers up to 5 sites.

👉 Uptime Monitor

A quick checklist for your own site

  • Does it redirect HTTP to HTTPS, and when does the certificate expire?
  • Do you have SPF and DMARC records? (No DMARC = easier to spoof your domain.)
  • Is the analytics tag you think is installed actually firing?
  • Are you loading libraries you no longer use (old jQuery plugins, a second analytics tag)?
  • Would you know within 10 minutes if the site went down at 2 AM?

If any of those made you go "hm", the two tools above will answer them in a minute.

I'm part of RizeHub, a small web studio in Davao City, Philippines. We build Shopify, Webflow and WordPress sites, and these tools came out of our own client work. Disclosure: both tools are ours, and both are free.