Encode and decode text using ROT13 and customizable Caesar shift ciphers.
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.
Choose ROT13 (+13) or customize the shift slider from 1 to 25.
Enter text to encode or decode.
Copy transformed cipher text.
ROT13 is a special Caesar cipher that rotates the alphabet by 13 positions; applying it twice restores the original text.
No, standard Caesar ciphers only rotate ASCII letters (A-Z, a-z).
Zero-egress companion tools in the Text Utilities suite
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Encode and decode reversible ROT13 and custom Caesar cipher text strings.
Format scientific Markdown chemical formulas and mathematical exponents.
