Build production Access-Control-Allow headers, preflight OPTIONS handlers, and Nginx/Next.js configs.
Execution runs 100% locally inside the browser sandbox using HTML5 Canvas, Web Cryptography Subtle API, and Web Workers. Zero egress.
Zero network latency. Operates completely offline with zero dependencies on third-party backend servers or cloud services.
Built according to official RFC specifications, cryptographic test vectors, and enterprise-grade data transformation standards.
Enter your frontend domain origin (e.g. https://app.example.com).
Choose allowed HTTP verbs and request headers.
Copy the raw HTTP headers or web server blocks.
Browsers strictly reject credentials (cookies/auth) if Access-Control-Allow-Origin is set to wildcard *.
It caches preflight OPTIONS responses in client browsers to reduce redundant network round trips.
Zero-egress companion tools in the Security & Network suite
Measure cryptographic randomness, Shannon entropy (0-8 bits/byte), Chi-square test, and byte distributions.
Brute-force all 256 single-byte XOR keys with automated English frequency & chi-squared scoring.
Audit CSP, HSTS, X-Frame-Options, and security headers with OWASP grading (A+ to F).
Compare memory hardness, GPU ASIC resistance, and security parameters across KDF standards.
