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Is This Website Built With Substack?

Paste any URL below. Our scanner checks 5 Substack-specific fingerprints — scripts, CDN domains, HTML attributes, and HTTP headers — and returns a confidence score instantly.

How to Tell if a Website Uses Substack

Identifying whether a website was built with Substack 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 5 Substack-specific signals, and returns a verdict with a confidence score.

You might want to detect Substack 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 Substack?

Substack is the largest and most influential newsletter and subscription platform, hosting hundreds of the world's top writers, journalists, and independent media outlets — including publications that have generated millions in annual subscriber revenue. It pioneered the paid newsletter model with simple 10% revenue sharing, a writer-friendly setup experience, and a built-in discovery network. Substack Recommendations has become a major growth channel, with reader suggestions driving new subscriber acquisition. Substack sites are identifiable through resources loaded from substackcdn.com for media and assets, the Substack JavaScript runtime on all publication pages, and distinctive *.substack.com subdomain patterns. Custom domain sites still load all media through substackcdn.com, making it a reliable detection signal. The platform is free to use with Substack taking 10% of paid subscription revenue.

It is primarily used for content-driven websites, blogs, news sites, documentation, and publishing platforms.

Visit Substack official website

Signs a Website Is Built With Substack

Our detection engine checks 5 unique Substack fingerprints. Here are the most reliable signals:

High Confidence

CDN Domain

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

substackcdn.com
High Confidence

JavaScript / Script Files

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

substack.comsubstackcdn.com
Medium Confidence

HTML Attributes & Class Names

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

substack
Medium Confidence

Meta Tags

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

substack

How to Manually Detect Substack 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 substack or substack
  4. If found in script src, class names, or meta tags — it's likely Substack

Method 2 — Browser DevTools Network Tab

  1. Press F12 to open DevTools
  2. Click the Network tab and reload the page
  3. Filter by substack in the search box
  4. If you see requests to Substack-specific domains, it's confirmed
Faster: Skip the manual steps — paste the URL into our scanner above and we check all 5 signals in seconds.

How Our Substack 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 5 Substack-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 Substack

Install Substack from https://substack.com, set up your content models, and connect a frontend framework like Next.js or Gatsby to display your content.

Other popular CMS platforms include WordPress, Ghost, Contentful, Sanity, and Strapi.

Get started with Substack

Frequently Asked Questions

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

The most reliable ways to detect Substack are: (1) open DevTools → Network tab and look for requests to Substack-specific CDN domains, (2) view page source and search for Substack-specific class names or data attributes, (3) use our free scanner — we check 5 detection signals automatically and return a confidence score.

Is your Substack detector free?

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

How accurate is the Substack detection?

We check 5 unique Substack 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 Substack 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 Substack website?

If you want to build something similar, visit https://substack.com 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.