Free Online Developer Tools
Fast, private, no-sign-up utilities for everyday development and design tasks. Everything runs in your browser.
Design Tools
Color Converter
Convert between HEX, RGB, HSL, HSV formats. Pick colors and copy values instantly.
Pixel to REM / EM
Convert pixels to REM or EM units. Set your base font size and get precise values.
Aspect Ratio Calculator
Calculate missing dimensions. Common ratios for video, images, and responsive design.
Text & Data Tools
JSON Formatter & Validator
Pretty-print, validate, and minify JSON. Tree view for easy inspection.
Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 strings back to plain text.
URL Encoder / Decoder
Encode special characters for URLs or decode percent-encoded strings.
Text & Word Counter
Count characters, words, sentences, and paragraphs. Real-time stats.
Markdown Preview
Write Markdown and see the rendered HTML preview side-by-side.