Free Developer Tools — JSON, Regex, JWT, SQL & More Online
Format and validate JSON, test regular expressions with live highlighting, decode JWTs, minify CSS, format SQL, encode URLs, parse cron expressions, encode HTML entities, and convert Base64 — all in your browser, all free.
All Developer Tools
JSON Formatter
Validate, format, and minify JSON with syntax highlighting.
DeveloperRegex Tester
Write, test, and debug regular expressions live.
DeveloperCSS Minifier
Minify CSS for faster page loads.
DeveloperBinary / Hex / Octal Converter
Convert between binary, hexadecimal, octal, and decimal.
DeveloperMarkdown to HTML
Convert Markdown to clean HTML with live preview.
DeveloperEmail Validator
Validate email addresses for correct format instantly.
DeveloperJWT Decoder
Decode and inspect JSON Web Token header, payload, and signature.
DeveloperSQL Formatter
Beautify and format SQL queries for readability.
DeveloperURL Encoder / Decoder
Encode or decode URLs and query string parameters instantly.
DeveloperCron Expression Parser
Parse and explain cron expressions in plain English.
DeveloperHTML Entities Encoder
Encode and decode HTML special characters and entities.
DeveloperXML Formatter
Format, minify, and validate XML documents instantly.
DeveloperYAML ↔ JSON Converter
Convert YAML to JSON and JSON to YAML instantly.
DeveloperText Diff Checker
Compare two texts side-by-side and highlight differences.
DeveloperColor Picker
Pick, convert, and explore colors in HEX, RGB, HSL, and CMYK.
DeveloperColor Contrast Checker
Check WCAG AA/AAA color contrast ratios for accessible design.
DeveloperCSS Gradient Generator
Build linear and radial CSS gradients visually with live code output.
DeveloperCSS Box Shadow Generator
Design CSS box shadows visually and copy the ready-to-use CSS.
DeveloperJSON Schema Validator
Validate JSON data against a JSON Schema (draft-07) in your browser.
DeveloperCron Expression Builder
Build cron expressions visually — select schedule and get the cron string.
DeveloperAbout Developer Tools
Developer tools should be fast, reliable, and private. Every tool in this collection loads instantly and works without sending your code to a server — critical when you're working with proprietary SQL queries, internal API tokens, or production JWT credentials.
The JSON Formatter validates your JSON in real time, highlights errors with line numbers, and lets you switch between pretty-printed and minified output. The Regex Tester provides live match highlighting, match count, named capture groups, and all standard flags (g, i, m, s, u, y) — making it far easier to debug complex patterns than trial and error in code.
The JWT Decoder reveals the complete header, payload, and claims of any JSON Web Token, including expiry time formatted in your local timezone. The SQL Formatter beautifies messy queries with proper indentation for SELECT, INSERT, UPDATE, DELETE, and complex JOINs. The Cron Expression Parser translates any 5- or 6-field cron string into plain English and shows the next 10 scheduled run times.
Additional tools include CSS Minifier for shrinking stylesheet file sizes, URL Encoder/Decoder for handling query parameters, HTML Entities Encoder for escaping special characters, Base64 Encode/Decode for data encoding tasks, Binary/Hex/Octal Converter for low-level work, and Hash Generator for computing checksums. All tools are keyboard-friendly and designed for developer workflows.
Frequently Asked Questions
What JSON features does the formatter support?
The JSON Formatter validates JSON syntax, highlights errors with line and column numbers, supports pretty-printing with 2 or 4 space indentation, and minifies JSON for production use.
Does the regex tester support all JavaScript flags?
Yes. The Regex Tester supports all standard JavaScript regex flags: global (g), case-insensitive (i), multiline (m), dotAll (s), Unicode (u), and sticky (y).
Is the SQL formatter aware of different SQL dialects?
The SQL Formatter uses a general ANSI SQL beautifier that works well with MySQL, PostgreSQL, SQLite, and MS SQL Server syntax. Dialect-specific keywords may not be perfectly indented in all cases.
Can I save my work between sessions?
Currently, work is not persisted between sessions. We recommend copying your formatted output to your editor or using your browser's local storage manually.
Is my JWT token sent anywhere when I decode it?
No. The JWT Decoder parses the token entirely in your browser using JavaScript's `atob()` and JSON parsing. Your token never leaves your device.