DevKit4U
Free, fast online developer tools for converting, formatting, encoding, and comparing data. Everything runs locally in your browser — no data leaves your device.
Converters
JSON / XML Converter
Convert between JSON and XML formats instantly with auto-detection and nested structure support.
CSV / JSON Converter
Convert between CSV and JSON with custom delimiters and header detection.
Timestamp Converter
Convert between Unix epoch timestamps and human-readable dates with timezone support.
Number Base Converter
Convert numbers between decimal, hex, octal, and binary with real-time updates.
Color Converter
Convert colors between HEX, RGB, and HSL formats with live visual preview.
Viewers & Formatters
JSON Viewer
View, format, and explore JSON with syntax highlighting, tree view, and minification.
XML Viewer
View, format, and explore XML with syntax highlighting, tree view, and minification.
SQL Formatter
Format and beautify SQL queries with support for multiple database dialects.
HTML Prettifier
Format, prettify, and minify HTML code with customizable indent and wrapping options.
CSS Formatter
Format, beautify, and minify CSS stylesheets with proper indentation.
Markdown Preview
Live Markdown to HTML preview with syntax-highlighted code blocks and side-by-side editing.
Text Tools
Diff Checker
Compare two texts side by side with line-level and character-level diff highlighting.
String Length
Count characters, words, lines, and byte size for any text instantly.
Regex Tester
Test regular expressions with real-time match highlighting and capture group display.
Lorem Ipsum Generator
Generate lorem ipsum placeholder text by paragraphs, sentences, or word count.
Encoders & Decoders
Base64 Encode / Decode
Encode and decode Base64 strings with full UTF-8 support and instant results.
URL Encode / Decode
Encode and decode URL components and query strings with special character handling.
JWT Decoder
Decode JWT tokens and inspect header, payload, claims, and expiration details.
HTML Entity Encoder
Encode and decode HTML entities including named and numeric character references.
Hash Generator
Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes securely in your browser.
Generators & Reference
UUID Generator
Generate random UUID v4 identifiers individually or in bulk with one-click copy.
QR Code Generator
Generate QR codes from text or URLs with customizable size and error correction.
Cron Expression Parser
Parse cron expressions to plain English descriptions with next scheduled run times.
JSON Schema Validator
Validate JSON data against a JSON Schema with detailed error messages and feedback.
HTTP Status Reference
Searchable reference for all HTTP status codes with descriptions and categories.