JSON formatter & validator
Format, beautify, validate, and minify JSON online. Pinpoint syntax errors by line and column, sort keys, and copy or download the result.
Caesar cipher
Encode and decode Caesar cipher, ROT13, and ROT47 text. Crack unknown shifts automatically with English frequency ranking.
How to use Caesar cipher
Encode and decode the Caesar cipher, the classic shift cipher, plus ROT13 and ROT47.
- Shift letters by any amount and keep case, spaces, and punctuation
- ROT13 (shift 13) undoes itself, and ROT47 also scrambles digits and symbols
- Crack an unknown shift: all 25 possibilities are ranked by how English they look
Fun for puzzles, geocaching, and teaching. It isn't real security.
Caesar cipher FAQs
Is Caesar cipher free?
Caesar cipher is a free online tool on ReallyUseful.Tools. No account is required.
Does Caesar cipher run in my browser?
Caesar cipher is designed to run in your browser where supported, so files can stay on your device instead of being uploaded to a server.
More Developer Tools
Base64 encode / decode
Encode text to Base64 or decode Base64 back to text with full UTF-8 support and an optional URL-safe alphabet.
Unix timestamp converter
Convert Unix epoch timestamps to human-readable dates and back. Supports seconds and milliseconds, local time, UTC, and ISO 8601.
Hash generator
Generate MD5, SHA-1, SHA-256, SHA-512, SHA3, and CRC32 hashes for text or files. Verify checksums and create HMACs locally.
Regex tester
Test JavaScript regular expressions with live match highlighting, capture groups, flags, and replace preview.