Free Code Development Tools — Regex Tester, CSS Minifier & More
Every developer needs a reliable set of utilities for daily coding tasks. Test regular expressions in real time, minify CSS for production, preview Markdown documentation, or convert colors between HEX, RGB, and HSL — all without leaving your browser.
These tools are designed for speed and simplicity. Paste your code, get instant results, and copy the output with one click.
Tools in This Category
Regex Tester
Test regular expressions online with real-time matching and highlighting. Free regex debugger tool.
CSS Minifier
Minify CSS code online. Remove whitespace, comments, and optimize your stylesheets. Free CSS compressor.
Markdown Preview
Write and preview Markdown in real time. Supports GFM tables, code blocks, and lists. Free online editor.
Color Converter
Convert colors between HEX, RGB, HSL formats. Free online color picker and converter tool.
Common Use Cases
- ✓ Test and debug regex patterns with real-time matching and highlighting
- ✓ Minify CSS files to reduce page load times
- ✓ Preview Markdown before committing to GitHub or publishing docs
- ✓ Convert colors between HEX, RGB, and HSL for CSS styling
- ✓ Validate regex syntax before embedding in application code
Related Categories
Frequently Asked Questions
Does the regex tester support all regex flavors?
The regex tester uses JavaScript's built-in RegExp engine, which supports most common patterns including lookahead, lookbehind (ES2018+), named groups, and Unicode property escapes.
How much can CSS minification reduce file size?
CSS minification typically reduces file size by 15-30% by removing whitespace, comments, and redundant code. Combined with gzip compression, total savings can reach 70-80%.
What Markdown features are supported in the preview?
Our Markdown preview supports GitHub Flavored Markdown (GFM) including tables, task lists, strikethrough, fenced code blocks with syntax highlighting, and autolinks.
Try These Tools Now
All tools are free, run in your browser, and require no signup.