Tech Stack Detector (Wappalyzer & BuiltWith alternative)

Give it a list of websites and it tells you what each one is built with: CMS, shop platform, analytics, marketing and chat tools, CDN, hosting, email provider and the SSL certificate. One row per website, ready for a spreadsheet or your CRM.

I use it for lead generation. A plumber still running a stock WordPress theme on shared hosting, with no booking widget and no chat, is a much warmer prospect for a web agency than a random name from Google Maps. Checking that by hand takes a few minutes per site. This goes through the whole list while you do something else.

It recognizes over 7,600 technologies. You pay per website that was actually analyzed. If a site doesn't load (dead domain, timeout, blocked), you still get a row explaining why, but it isn't charged.

Example

Input:

{ "urls": ["joesplumbingandheating.com", "ghost.org", "basecamp.com"] }

One of the rows you get back (shortened, real output):

{
  "inputUrl": "https://joesplumbingandheating.com",
  "domain": "joesplumbingandheating.com",
  "statusCode": 200,
  "title": "Joe's Plumbing and Heating - Your home comfort starts here!",
  "techCount": 15,
  "techNames": ["Cloudflare", "WordPress", "MySQL", "GoDaddy", "PHP", "Yoast SEO",
                "WordPress Block Editor", "GoDaddy CoBlocks", "Twenty Twenty-Two", "..."],
  "technologies": [
    { "name": "WordPress", "version": null, "categories": ["CMS", "Blogs"], "confidence": 100, "website": "https://wordpress.org" },
    { "name": "Yoast SEO", "version": "28.5", "categories": ["SEO", "WordPress plugins"], "confidence": 100, "website": "https://yoast.com/wordpress/plugins/seo/" }
  ],
  "categories": { "CDN": ["Cloudflare"], "CMS": ["WordPress"], "Hosting": ["GoDaddy"] },
  "emailProvider": null,
  "hosting": "GoDaddy",
  "sslIssuer": "Google Trust Services",
  "sslExpiresAt": "Nov 12 10:38:42 2026 GMT",
  "sslValid": true,
  "sslError": null,
  "error": null,
  "checkedAt": "2026-09-29T09:05:51+00:00"
}

Every row has the same set of fields. If something couldn't be determined, it's null rather than missing, so exports to CSV/Excel don't shift columns.

A few fields worth knowing about:

• emailProvider comes from the domain's MX records (Google Workspace, Microsoft 365, Zoho, Proofpoint...). If the provider isn't one I recognize, you get the MX host itself.
• hosting is the most specific hosting/CDN signal found. Treat it as a hint; sites behind Cloudflare often hide the real host.
• sslValid / sslError tell you if the certificate is expired, mismatched or missing. Handy for spotting neglected sites.

Input

Field	What it does	Default
urls	Domains (example.com) or full URLs. Duplicates are dropped.	required
maxItems	Cap on websites per run	1000
checkDns	Look up MX/TXT/NS records (email provider, tools verified via DNS)	on
maxConcurrency	Sites checked in parallel	20
requestTimeoutSecs	How long to wait for a slow site	20

Things people use it for

Finding prospects by what they're missing (no analytics, no booking tool, outdated CMS), adding "runs Shopify / HubSpot / Salesforce" to a lead list before outreach, checking what competitors use for payments, ads or email, and measuring how common a tool is across a list of sites.

You can schedule it, call it from the API, or plug it into n8n, Make, Zapier or Google Sheets through the usual Apify integrations. It also works as a tool for AI agents via the Apify MCP server.

FAQ

Why not just use Wappalyzer or BuiltWith? They're good, but their APIs are subscriptions. If you check a few hundred sites a month, paying per site is a lot cheaper.

Does it run a browser? No. It reads the HTML, response headers, cookies, script and meta tags, DOM selectors, DNS records and the TLS certificate. That catches almost every CMS, shop, analytics and marketing tool and keeps runs fast and cheap. The trade-off: a tool that only shows up after JavaScript runs in the browser can occasionally be missed.

A site came back with an error. The error field says why: the domain doesn't resolve, the site timed out, or it answered 403/429 (some big sites block automated requests). Those rows aren't charged.

How do I track changes over time? Run it on a schedule and compare techNames between runs, for example in Google Sheets.

Notes

Only public pages are read. No logins, no personal data.

Detection rules come from webappanalyzer (GPL-3.0), the community-maintained continuation of the open-source Wappalyzer rules. I update them regularly.

If you're prospecting for a web agency, Website Audit & Lead Scorer uses the same detection and adds a lead score, the list of site problems and a first outreach line for each business.

Found a site it gets wrong? Open an issue with the URL and I'll take a look.