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Is This Website Built With Builder.io?

Paste any URL below. Our scanner checks 6 Builder.io-specific fingerprints — scripts, CDN domains, HTML attributes, and HTTP headers — and returns a confidence score instantly.

How to Tell if a Website Uses Builder.io

Identifying whether a website was built with Builder.io used to require technical expertise — inspecting source code, tracing network requests in DevTools, and knowing which patterns to look for. Our free scanner automates all of that: it fetches the page, analyzes 6 Builder.io-specific signals, and returns a verdict with a confidence score.

You might want to detect Builder.io for competitive research, due diligence before acquiring a site, or simple curiosity. Whatever the reason, this page covers every method — automated and manual.

What is Builder.io?

Builder.io is a visual headless CMS that works with any frontend framework. Sites using Builder.io load scripts from cdn.builder.io and include builder-component attributes in their markup.

It is primarily used for web applications, internal tools, customer portals, and SaaS products — without writing code.

Visit Builder.io official website

Signs a Website Is Built With Builder.io

Our detection engine checks 6 unique Builder.io fingerprints. Here are the most reliable signals:

High Confidence

CDN Domain

Assets (images, scripts, fonts) are loaded from Builder.io-specific CDN domains. This is one of the most reliable signals because CDN domains are hard to hide.

cdn.builder.io
High Confidence

JavaScript / Script Files

Builder.io loads specific JavaScript runtime files or loads scripts from identifiable URLs. Checking script src attributes reveals the platform.

builder.iocdn.builder.io
Medium Confidence

HTML Attributes & Class Names

Builder.io injects proprietary class names, data attributes, or markup patterns into the page HTML that are unique to the platform.

builder-componentdata-builder-
Medium Confidence

Meta Tags

Some Builder.io sites include a generator meta tag or other platform-specific meta elements in the document head.

builder.io

How to Manually Detect Builder.io Websites

Method 1 — View Page Source

  1. Open the website in your browser
  2. Press Ctrl+U (Windows) or Cmd+Option+U (Mac)
  3. Search (Ctrl+F) for builder-io or builder.io
  4. If found in script src, class names, or meta tags — it's likely Builder.io

Method 2 — Browser DevTools Network Tab

  1. Press F12 to open DevTools
  2. Click the Network tab and reload the page
  3. Filter by builder in the search box
  4. If you see requests to Builder.io-specific domains, it's confirmed
Faster: Skip the manual steps — paste the URL into our scanner above and we check all 6 signals in seconds.

How Our Builder.io Detector Works

When you submit a URL, our engine fetches the page from its server — just like a browser would — then analyzes the response across 6 Builder.io-specific fingerprints:

Script analysis

We scan all loaded JavaScript files for known CDN paths and runtime names

CDN domain matching

We cross-reference every asset request against known platform CDNs

HTML pattern scanning

We search the DOM for platform-specific class names and data attributes

Header inspection

We read HTTP response headers that identify the server or platform

Meta tag extraction

We check generator and other meta tags in the document head

Confidence scoring

We weight each matched signal and normalize to a 0–99% score

How to Build a Similar Website With Builder.io

Visit https://builder.io and describe the app you want to build. The AI generates the frontend and often the backend logic too. You can connect databases, add authentication, and deploy with one click.

Other popular AI app builders include Bolt.new, Lovable, Bubble, Replit, and FlutterFlow.

Get started with Builder.io

Frequently Asked Questions

How can I tell if a website was built with Builder.io?

The most reliable ways to detect Builder.io are: (1) open DevTools → Network tab and look for requests to Builder.io-specific CDN domains, (2) view page source and search for Builder.io-specific class names or data attributes, (3) use our free scanner — we check 6 detection signals automatically and return a confidence score.

Is your Builder.io detector free?

Yes, completely free. Paste any URL into our scanner and we'll analyze it for Builder.io fingerprints immediately. No account required, no limits on scans.

How accurate is the Builder.io detection?

We check 6 unique Builder.io fingerprint signals across HTML, JavaScript, CDN domains, meta tags, and HTTP headers. Our confidence score reflects how many signals matched — a score above 70% is a strong indicator. We cap accuracy at 99% to reflect that all fingerprint-based detection is probabilistic.

Can Builder.io sites be detected if they use a custom domain?

Yes. Custom domains don't hide the underlying platform. The JavaScript files, CDN requests, HTML attributes, and server headers all remain identifiable regardless of the domain name used. Our scanner fetches the page directly and analyzes its technical composition.

What should I do after detecting a Builder.io website?

If you want to build something similar, visit https://builder.io to learn more or sign up. If you're doing competitive research, our scan result also shows the full technology stack — including hosting platform, domain age, and other detected technologies. You can share the result link with your team.