How to detect Replit Agent websites
Replit's AI agent that builds full apps from descriptions
Replit Agent is an AI coding assistant built into Replit that can create entire web applications from natural language. Apps created this way are often hosted on Replit's own infrastructure (*.replit.app, *.repl.co) or deployed to external hosts. The Replit-hosted variants are trivially detectable; custom deployments require looking at code-level markers.
Technical fingerprints
- ✓
Subdomain on replit.app or repl.co - ✓
replit.dev URLs in HTML source - ✓
replit- prefix in CSS class names or data attributes - ✓
CDN references to replit's asset hosting - ✓
CNAME pointing to proxy.replit.com or similar - ✓
replit-/i pattern in script paths
Visual design patterns
- →Functional, utilitarian design — Replit Agent prioritises working code over aesthetics
- →React with Tailwind CSS (most common), sometimes plain CSS
- →shadcn/ui or Chakra UI depending on scaffold
- →Simpler layouts than Lovable or v0 — less emphasis on gradients
- →Express or Hono backend visible in API route patterns
Typical tech stack
Frequently asked questions
Are all replit.app sites built with Replit Agent?+
No — replit.app is also used by developers who hand-code their projects on Replit. The Agent marker is more specific, but in practice any site on a replit.app subdomain has a higher prior probability of being AI-generated.
How do I detect a Replit app deployed to a custom domain?+
Look for Replit-specific CDN URLs, replit- CSS prefixes, or code comments mentioning Replit. Our confidence scoring combines these with visual design patterns — a Replit app on a custom domain may score in the 30–50% range without the subdomain signal.
Does Replit Agent use shadcn/ui?+
Sometimes, but less consistently than Lovable or v0. Replit Agent tends to produce more varied stacks depending on the prompt. Chakra UI, plain Tailwind, and Material UI are all common outputs.
Detect other platforms