Substack is the largest newsletter and subscription platform, used by writers, journalists, and creators. Substack sites load resources from substackcdn.com and include the Substack JavaScript runtime. It powers millions of paid and free newsletters worldwide.
Paste any URL to instantly detect whether it was built with Substack. Our engine checks 4 technical signals.
Substack is used across many industries. These are the most common website types built on this platform:
Publishers & bloggers
Flexible content management with rich plugin ecosystems
Enterprise businesses
Scalable CMS with extensive customization
NGOs & nonprofits
Affordable open-source platform with wide community support
E-commerce retailers
WooCommerce integration for product catalogs
Every Substack website leaves distinctive technical fingerprints. Here's what to look for:
CDN Domains
Network requests to these domains are a reliable indicator:
substackcdn\.comJavaScript Patterns
2 script patterns linked to Substack
HTML Attributes
1 HTML pattern in the page source
Explore how Substack compares to similar cms tools: