BuiltWith and Wappalyzer both answer the question "what is this website built with?" They look at signals on a page, such as scripts, headers, cookies and markup patterns, and match them to a database of technologies. This page compares them honestly and shows how to verify a result yourself, because detection tools guess, and sometimes guess wrong. SiteDownCheck is not a technology database, so this is a guide to the field rather than a pitch.
Details come from each vendor's public pages at the time of writing (October 2026). We do not quote prices because plans change; check their pricing pages.
What each is for
BuiltWith describes itself as a web technology lookup service. Its plans page says individual site lookups are free, and paid plans (Basic, Pro, Team and above) add reports and lists, such as finding sites using a given technology, along with exports and long historical trend data. It also mentions CRM integration and API access.
Wappalyzer is best known for its browser extension and its lookup tool. Its pricing page lists a free account with a monthly allowance of technology lookups and a small number of website alerts, with paid plans adding more lookups, users, lead lists and API credits. Which features, such as the extension, sit on which plan has changed over time, so verify before you plan around it.
Side-by-side
| BuiltWith | Wappalyzer | |
|---|---|---|
| Single-site lookup | Free per their plans page | Free account with a monthly lookup allowance per their pricing page |
| Lists of sites using a technology | Paid plans | Paid plans (lead lists) |
| Historical data | Emphasized on their site | Check their docs |
| Browser extension | Check their site | Well-known; plan availability varies, check current pricing |
| API | Plan-based | Credit-based per their pricing page |
| Typical user | Sales, market research, competitive analysis | Developers, sales, agencies |
| Alerts | Check their site | A small number on the free account per their page |
Choosing between them
- Occasional look at one site: either free lookup works. Try both; results will differ.
- Building prospect lists: this is the paid use case for both. Compare the size of their databases for the technologies you care about and test with a few sites you know.
- Competitive research over time: historical data matters; check what each offers for your needs.
- Developer convenience: an in-browser extension saves time. Confirm what your plan includes.
Why detection results disagree
Both tools infer. A technology is reported when a signature matches, for example a script URL, a meta generator tag, a cookie name or a response header. That leads to predictable errors:
- Hidden or removed signatures. Security-conscious sites strip generator tags and version headers.
- Proxies and CDNs. Cloudflare or another CDN hides the origin server and software.
- Server-side tools. Backends that never touch the page, such as a database, are mostly invisible.
- Stale data. A technology removed last month may still be listed.
- Lookalikes. Different products can share a script name or class pattern.
How to check a result yourself
You can verify most claims in a few minutes.
- Response headers.
Server,X-Powered-By,Viaand cache headers hint at the stack. Use the HTTP header checker. - CDN. The CDN detector shows whether a CDN sits in front.
- Hosting. The website hosting checker identifies the provider from the IP and ASN.
- Third-party scripts. The third-party script checker lists analytics, chat, tag managers and ad scripts a page loads.
- Meta tags. The meta tag checker shows
generatorand other tags. - Cookies. The cookie checker shows cookie names that often identify a platform or framework.
- Page source. View source and search for
wp-content,cdn.shopify.comor framework-specific markers.
None of these is proof, but agreement across several is strong evidence.
Use with care
Looking at a public page's technology is routine, but scraping bulk lists, contacting people from purchased contact data and using the information for outreach come with legal obligations such as consent rules in many jurisdictions. Review each vendor's terms and the rules that apply to you. Also remember that exposing your own stack helps attackers target known vulnerabilities; consider trimming version headers, as discussed in the HTTP security headers guide.
Honest limitations of ours
We do not maintain a technology-signature database or offer prospect lists. Our tools help you confirm specific facts about a site, not map every technology on it.
अगले कदम
- Check the CDN with the CDN detector.
- Identify the host with the website hosting checker.
- Inspect headers with the HTTP header checker.
- Review scripts with the third-party script checker.
- Learn what a CDN does in CDN explained.
सामान्य प्रश्न
Is BuiltWith free?
Per its plans page, individual site lookups are free; lists, reports and larger usage need a paid plan.
Is Wappalyzer free?
It offers a free account with a limited monthly lookup allowance, according to its pricing page. Check what is included before relying on it.
Why does a tool miss my site's CMS?
Signatures may be removed, or a CDN or custom theme hides them. Detection is inference, not certainty.
Can I hide my tech stack?
You can reduce what is exposed, such as version headers and generator tags, but you cannot fully hide it. Do not rely on obscurity for security.
Try SiteDownCheck free
3 monitors, 5-minute checks, email and webhook alerts and a public status page. No credit card.
मुफ़्त मॉनिटरिंग शुरू करेंOpinions here are our own; verify vendor details yourself. See our संपादकीय नीति और अस्वीकरण.