Encoding & Decoding Tools
Base64, Base64URL, percent-encoding, HTML entities, hexadecimal, binary and JWT. Encode and decode text without sending it anywhere.
Base64, Base64URL, percent-encoding, HTML entities, hexadecimal, binary and JWT. Encode and decode text without sending it anywhere.
Base64 Encoder / Decoder
Two-way text conversion, correct for UTF-8 and for the URL-safe alphabet.
URL Encoder / Decoder
Percent-encoding that gets the space-versus-plus distinction right.
HTML Entity Encoder / Decoder
Turn markup-significant characters into entities, and read them back.
JWT Decoder
Read a token's claims and expiry without sending the token anywhere.
Hex Encoder / Decoder
Two hex characters per byte, in both directions.
ROT13 Cipher
A thirteen-place letter shift that undoes itself — obfuscation, not secrecy.
Query String Parser
Every parameter, decoded, with repeated keys shown as a list rather than silently overwritten.
Binary / Text Converter
Eight bits per ASCII character, with the code points shown alongside.
Why these run locally
Every tool on this page processes its input in the browser tab. For this category that matters because the inputs are frequently sensitive: digests of passwords and keys, authentication tokens, spreadsheet exports containing personal data, photographs of identity documents. None of that is transmitted, and the tools keep working if you disconnect from the network after the page loads.
Other categories
- Hash & Checksum tools — Generate MD5, SHA-1, SHA-256, SHA-512 and HMAC digests, and verify a downloaded file against a published checksum — all computed in your browser.
- Text Tools tools — Count words, convert naming conventions, deduplicate and sort lists, generate slugs and placeholder text, and extract structured values out of prose.
- Data Converters tools — Convert between JSON, CSV, YAML and XML with correct escaping, type handling and error reporting — plus a strict JSON validator.
- Image Tools tools — Compress, resize and convert images in the browser.
- PDF Tools tools — Assemble JPEG and PNG files into real PDF documents.