Encoding, hashing, and QR
Encode and decode Base64, URLs, Unicode, hashes, QR codes, and common developer data formats.
Recommended tools
Base64
Encode and decode text or files. 100% free, runs locally in your browser—nothing is uploaded to our servers.
URL Encode / Decode
Common encode/decode scenarios. 100% free, runs locally in your browser—nothing is uploaded to our servers.
Hex (Hexadecimal)
Convert between UTF-8 bytes and hexadecimal. 100% free, runs locally in your browser—nothing is uploaded to our servers.
Hash Digest
MD5, SHA-256, and other checksums and digests. 100% free, runs locally in your browser—nothing is uploaded to our servers.
QR Code Generator
Generate PNG from text, URL, WiFi, etc. 100% free, runs locally in your browser—nothing is uploaded to our servers.
QR Code Decoder
Parse QR code from image (jsQR). 100% free, runs locally in your browser—nothing is uploaded to our servers.
Unicode Encode/Decode
Convert between text and Unicode escape sequences (\uXXXX, &#xXXXX;, etc.). 100% free, runs locally in your browser—nothing is uploaded to our servers.
Random Password / Token
Configurable length and charset, crypto-secure random. 100% free, runs locally in your browser—nothing is uploaded to our servers.
Guides and analysis
Base64 Encoding/Decoding Explained: From Concepts to Practical Applications
Deep dive into Base64 encoding/decoding principles, use cases, and caveats, including Base32/Base58 variants and applications in URLs, images, JWT, emails, and common pitfalls.
Complete Guide to URL Encoding: Percent-Encoding Principles and Practice
From URL structure to percent-encoding rules—explains the difference between encodeURIComponent and encodeURI, and how to handle Chinese parameters, special characters, and internationalized domain names correctly.
Complete Guide to Hashing and Encryption: Using MD5, SHA256, and AES Correctly
From hash functions to symmetric and asymmetric encryption—covers MD5, SHA256, HMAC, and AES: how they work, when to use them, and common security mistakes to avoid.
The Complete QR Code Guide: How They Work, Batch Generation, and Artistic QR Codes
Ordering food by scan, adding WeChat, joining Wi-Fi, paying—QR codes are everywhere. This article starts from QR Code structure and Reed-Solomon error correction, explaining error-correction levels, quiet zones, contrast, capacity limits, how to generate in bulk, make artistic and Wi-Fi QR codes, plus a practical checklist so your codes always scan.