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Developer Tools

Free Developer Toolkit

Essential tools for developers — JSON formatter, Base64, Regex tester, Color picker, UUID generator, Hash generator, HTML encoder and more. All run in your browser, private & instant.

12
Tools
100%
Private
0
Server Calls
{ } JSON 🔐 Base64 🔍 Regex 🎨 Color 🔑 UUID 🔒 Hash 🌐 HTML Encode 🔗 URL Encode 🪙 JWT Decoder 📄 Text Diff 🗜️ CSS Minifier 📝 Markdown
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JSON Formatter & Validator
Beautify, minify, validate and analyse your JSON data
🔥 Popular
Input JSON Paste your JSON here
Output
Output will appear here...
Base64 Encoder / Decoder
Encode or decode any text or data to/from Base64 format
Input
Output
Output appears here...
Regex Tester
Test regular expressions with live match highlighting and group capture
🔥 Popular
Regular Expression
Test String
Highlighted Matches
Color Picker & Converter
Pick colors and convert between HEX, RGB, HSL, CMYK and CSS variables
CSS Output
Shades & Tints
Contrast Info
UUID / GUID Generator
Generate v4 UUIDs, NanoIDs and custom unique identifiers
Generated IDs
Click Generate...
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Hash Generator
Generate MD5, SHA-1, SHA-256, SHA-512 hashes from any text
✨ New
Input Text
Hash Values
Hash values will appear here...
HTML Encoder / Decoder
Encode special characters to HTML entities and decode them back
Input
Output
Output appears here...
URL Encoder / Decoder
Encode or decode URLs and query string parameters
Input
Output
Output appears here...
JWT Token Decoder
Decode and inspect JWT tokens (Header, Payload, Signature) — no secret needed
JWT Token
Decoded Payload
Decoded JWT parts appear here...
Text Diff Checker
Compare two text blocks and highlight additions, deletions and changes
Text A (Original)
Text B (Modified)
CSS Minifier & Beautifier
Minify CSS to reduce file size or beautify compressed CSS for readability
Input CSS
Output
Output appears here...
Markdown Preview
Write Markdown and see a live preview rendered as HTML
✨ New
Markdown Input
Live Preview
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⚠️

Educational use only. All tools and course content on SmartUtilz are for informational and study purposes. Results must be independently verified by a qualified engineer before use in any design or safety-critical application. Read full disclaimer →