Is This Website Built With Ruby?

How to Tell if a Website Uses Ruby

Identifying whether a website was built with Ruby 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 2 Ruby-specific signals, and returns a verdict with a confidence score.

You might want to detect Ruby 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 Ruby?

Ruby is a programming language best known for Ruby on Rails, but also used for Sinatra, Discourse, Redmine and Jekyll-built sites. AIWebsiteDetector reports Ruby from Server banners of Ruby application servers (Phusion Passenger, Puma, Unicorn, Thin, WEBrick), an `X-Powered-By` value naming Ruby or Passenger, a versioned generator tag of a known Ruby application, and from a detected Ruby on Rails site. Behind a proxy that rewrites these headers, Ruby sites show nothing.

It is primarily used for business websites, portfolios, landing pages, and personal sites without coding knowledge.

Visit Ruby official website

How to Manually Detect Ruby Websites

Method 1 — View Page Source

Open the website in your browser
Press Ctrl+U (Windows) or Cmd+Option+U (Mac)
Search (Ctrl+F) for ruby or ruby
If found in script src, class names, or meta tags — it's likely Ruby

Method 2 — Browser DevTools Network Tab

Press F12 to open DevTools
Click the Network tab and reload the page
Filter by ruby in the search box
If you see requests to Ruby-specific domains, it's confirmed

Faster: Skip the manual steps — paste the URL into our scanner above and we check all 2 signals in seconds.

How Our Ruby 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 2 Ruby-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

Frequently Asked Questions

How can I tell if a website was built with Ruby?

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

Is your Ruby detector free?

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

How accurate is the Ruby detection?

We check 2 unique Ruby 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 Ruby 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 Ruby website?

If you want to build something similar, visit https://www.ruby-lang.org 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.