Website Tech Stack Detector: BuiltWith & Wappalyzer Alternative

Pricing: $10.00 per 1,000 websites checked, in every mode.

What does Website Tech Stack Detector do?

For each website: every technology it detects (CMS, shop system, analytics and tag managers, JavaScript frameworks, CDN, hosting, payment, marketing tools and more, from the fingerprints of 6,500+ technologies), with categories and versions where visible, grouped by category. On a schedule it lists only the sites whose stack changed, with the technologies added and removed.

Run it once, or schedule it to tell you when a site adds or drops a technology. The tool remembers what it has seen, in a storage in your own Apify account.

What you get

Detects	CMS, shop systems, analytics and tag managers, JavaScript frameworks, CDN, hosting, payment, marketing tools and more
Fingerprints	6,500+ technologies (the open-source webappanalyzer project), with categories and versions where visible
Per site	Technologies grouped by category; on a schedule, the technologies added and removed
Speed	One request per site (no browser), up to 25 seconds of analysis
Price	$10.00 per 1,000 websites checked, in every mode

Use cases

• Lead generation: find shops on a given platform, or sites using a competitor's tool.
• Watch competitors and get alerted when they add or drop a tool.
• Audit a portfolio of sites.

Input

Field	What it does
URLs	Websites, one per line
Track versions	Count version changes as changes (off by default)
Max websites	The most websites per run
Output mode	All results, only new results, or new + changed + removed results

Output

One row per website:

{
  "id": "site:apify.com",
  "changeType": "changed",
  "technologyNames": ["Cloudflare", "Google Tag Manager", "Next.js", "React"],
  "categories": {"JavaScript frameworks": ["Next.js", "React"], "Tag managers": ["Google Tag Manager"]},
  "added": ["Next.js"],
  "removed": ["Gatsby"]
}

Every row has every key (null when there's no value). changeType is new, changed, unchanged or removed; a changed row lists changedFields and the previous values. If a source fails or rate-limits the request, you get one row with changeType: "status" and a statusCode instead of an error, and it's free.

Schedule it

1. Fill in the input and save it as a task.
2. Run it once with Baseline only switched on: it remembers the current results and lists nothing. Or skip this and accept that the first scheduled run lists everything once.
3. Set Output mode to Only new results or New, changed and removed, and add a schedule.
4. Connect an integration (Slack, Google Sheets, Zapier, Make, n8n), or put a webhook URL in the input.

Each saved task keeps its own memory; switching a task between modes keeps it. Each run saves a summary (OUTPUT in the run's key-value store) with the counts.

Apify webhook template (Integrations → Webhook → payload):

{"datasetUrl": "https://api.apify.com/v2/datasets/{{resource.defaultDatasetId}}/items?clean=true&format=json"}

How much does it cost?

• $10.00 per 1,000 websites checked (on paid Apify plans 10-30% less). In 'changes' mode you pay for every website checked, but only the changes are listed.
• Example: checking 1,000 websites costs $10.00; checking 50 websites every day costs about $15.00 a month (plus Apify's start fee: $0.00010 per run).
• Status rows (errors) are free. Set a spending limit on the run and the tool stops there.

Good to know

• Detection reads the page, its headers, cookies and scripts in one request (no browser), so technologies that only show up after JavaScript runs can be missed: most often analytics, chat and A/B-testing tools that a tag manager loads later (the tag manager itself is found).
• Each site gets up to 25 seconds of analysis; a page that takes longer is listed with an error, free.
• You pay for every item checked in every mode. 'New, changed and removed' only filters the output to what changed since the last run, so a scheduled check lists nothing when all is the same.
• You choose the sites to check; check only sites you're allowed to. The tool makes one normal request per page (no crawling) with a clear bot name.

How it compares

Instead of	With this tool
Checking sites one by one in a browser extension	A whole list in one run, as a table you can filter
A headless-browser crawl	One normal request per site: fast and light, but tools loaded later by JavaScript can be missed
Re-checking a list by hand	'Changes' mode lists only the sites whose stack changed, with what was added or removed

FAQ

How accurate is it? It matches the page, its headers, cookies and scripts against the fingerprints of 6,500+ technologies. Tools that a tag manager loads later with JavaScript (often analytics, chat and A/B testing) can be missed; the tag manager itself is found.

Can I find all sites that use a technology? No: you give the websites, and it tells you what each one uses. Filter the results to build lists, for example all Shopify shops in your list.

Can it alert me when a competitor changes tools? Yes. Save the list as a task, set Output mode to 'New, changed and removed results' and add a schedule.

What does it cost on a schedule? Every website checked costs $0.01, in every mode; the 'changes' mode only filters the output to what changed.

Can I check a site by hand? For one site, yes: open the page source and the response headers and look for known traces, such as wp-content (WordPress), cdn.shopify.com (Shopify), gtag( (Google Analytics) or an x-powered-by header. Doing that well across 6,500+ technologies is the job of the open-source webappanalyzer fingerprint set, which this tool runs on every site in your list. It costs $10.00 per 1,000 websites checked, in every mode, including scheduled 'changes' runs.

Source: the websites you provide. Fingerprints: the open-source webappanalyzer project by Enthec (GPL-3.0), pinned to commit eea872a. Not affiliated with Enthec or Wappalyzer.

More Afterstar tools

• Website Screenshots - Bulk, Full Page & Visual Change Alerts: Screenshots of many web pages (desktop or mobile, full page), and alerts when a page visually changes.

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