Dev Utility Hub

Free online developer tools for everyday tasks. All processing happens in your browser.

Time & Date

KST ↔ UTC Converter
Time & Date
Convert between Korean Standard Time and UTC timestamps
Unix Timestamp Converter
Time & Date
Convert Unix timestamps to human-readable dates and vice versa
Date Calculator
Time & Date
Calculate differences between dates or add/subtract days
Cron Expression Parser
Time & Date
Parse, validate, and understand cron expressions with human-readable descriptions

Text & Data

JSON Formatter
Text & Data
Format, validate, and beautify JSON data
JSON ↔ YAML Converter
Text & Data
Convert between JSON and YAML formats
Text Diff
Text & Data
Compare two texts and highlight differences
Regex Tester
Text & Data
Test and debug regular expressions with live matching
Markdown Preview
Text & Data
Preview Markdown with live rendering
Case Converter
Text & Data
Convert text between different cases (camelCase, snake_case, etc.)

Encoding & Hashing

Base64 Encoder/Decoder
Encoding & Hashing
Encode and decode Base64 strings
URL Encoder/Decoder
Encoding & Hashing
Encode and decode URL parameters and components
Hash Generator
Encoding & Hashing
Generate MD5, SHA-1, SHA-256, and other hash values
JWT Decoder
Encoding & Hashing
Decode and inspect JSON Web Tokens
UUID Generator
Encoding & Hashing
Generate UUIDs (v4) for unique identifiers