Free Online Developer Tools
Fast, private, browser-based. No sign-up required. Works offline.
JSON Formatter
Prettify, minify, and validate JSON instantly in your browser.
Base64 Encode / Decode
Encode text to Base64 or decode Base64 back to plain text.
UUID Generator
Generate v4 UUIDs instantly — single or batch.
URL Encode / Decode
Encode or decode URL components and query strings.
Text Case Converter
Convert text to UPPER, lower, Title, camelCase, snake_case, and more.
Markdown Preview
Live Markdown editor with real-time HTML preview. Supports GFM tables, task lists, and code blocks.
Color Converter
Convert colors between HEX, RGB, and HSL formats with a live color preview.
Regex Tester
Test regular expressions in real time with match highlighting and capture group details.
Hash Generator
Generate MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes from any text.
Timestamp Converter
Convert Unix timestamps to human-readable dates and vice versa. Auto-detects seconds vs milliseconds.
JWT Decoder
Decode and inspect JWT header, payload, and signature. Highlights expiry status and timestamp claims.
Diff Checker
Compare two texts line by line and highlight additions and deletions. Powered by LCS algorithm.
Password Generator
Generate cryptographically secure passwords. Customize length and character sets with entropy meter.
QR Code Generator
Generate QR codes from URLs, text, Wi-Fi credentials, and more. Download as PNG.
Cron Expression Parser
Parse and explain cron expressions in plain English. Preview next 10 scheduled run times.
Latest Articles
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Regex Cheat Sheet with Live Tester
A practical regex reference covering character classes, quantifiers, anchors, groups, and lookaheads — with examples and a free online regex tester.
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Base64 Encoding Explained: What It Is and How to Use It
Understand what Base64 encoding is, why it exists, how to encode and decode in JavaScript, Python, and the command line — plus a free online Base64 tool.
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JSON Formatter Online: The Complete Guide
Learn how to format, validate, and debug JSON instantly. Covers syntax rules, common errors, and best practices — plus a free online JSON formatter tool.