How do I secure my Replit app?

Start by storing all sensitive values in Replit Secrets rather than hardcoding them in source files. Implement input validation and output encoding on all user-facing endpoints to prevent XSS and injection attacks. Add rate limiting middleware to protect against brute force and denial-of-service attempts. Set security headers like Content-Security-Policy, X-Frame-Options, and Strict-Transport-Security in your application responses. UNPWNED provides a comprehensive security scan of your Replit app that identifies exactly which protections are missing and gives you step-by-step instructions to fix each issue.