Clerk is a hosted user-management and authentication platform aimed at modern JavaScript frameworks (especially Next.js), providing pre-built sign-in/sign-up UI components, session management, and organization/team features out of the box — popular with startups and indie hackers who want auth working in minutes. Our engine detects Clerk through 3 script patterns tied to its client SDK and 2 HTML patterns matching its distinctive pre-built component markup, giving it a fairly strong, consistent signal. As a hosted platform, detection confirms a live integration with Clerk's managed backend. Documented at clerk.com.
Detect Clerk Websites — Free Tool
Enter any URL to check if it was built with Clerk. Instant results, no account required.
How we detect Clerk — see our methodology: AI Influence Score calculation, evidence tiers, and fingerprint signal types.
How to Detect Clerk Websites
Script Patterns
3 patterns
HTML Patterns
2 patterns
1. Check the Page Source
Open the website in your browser, right-click, and select "View Page Source". Search for clerk-specific patterns in the HTML.
2. Look for Script Files
Check the Network tab in DevTools for JavaScript files loaded from Clerk domains.
4. Use AI Website Detector (Easiest)
Our automated scanner checks all these signals at once and gives you an instant confidence score. Just enter any URL above.
Frequently Asked Questions
Is this website built with Clerk?
You can detect if any website was built with Clerk by using our free scanner above. Just enter the URL and we'll analyze HTML patterns, JavaScript files, CDN domains, and HTTP headers to determine if Clerk was used — with a confidence score.
How to detect if a website was built with Clerk?
There are several ways to detect Clerk: (1) View the page source and look for Clerk-specific class names or script URLs, (2) Check the Network tab in DevTools for requests to Clerk CDN domains, (3) Use our free tool — we check 5 detection signals automatically.
What websites are built with Clerk?
Clerk is used by thousands of websites worldwide. Our scanner has detected many Clerk-built sites across different industries. You can scan any URL to check if it uses Clerk.
How accurate is the Clerk detection?
Our Clerk detection engine checks 5 unique fingerprint signals, achieving high confidence results. We score each match and return a confidence percentage so you know how certain the detection is.
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Detection Info
- Category
- Auth Provider
- Signals Used
- 5 patterns
- Accuracy
- High
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