Tools
Free Online Toolbox
Simple, practical and free. Every tool works right away with no login; your input is processed only in your browser and never uploaded to any server.
JSON Formatter
Format, minify and validate JSON, with exact parse-error locations.
Text & Character Counter
Real-time character, word and paragraph counts for Chinese and English.
URL Encoder / Decoder
URL encode / decode with one click and clear feedback on bad input.
Base64 Encoder / Decoder
Base64 encode / decode with full UTF-8 (Chinese) and special-char support.
UUID Generator
Batch-generate UUID v4 with the Web Crypto API.
Password Generator
Configurable strong-password generator that runs entirely on your device.
Timestamp Converter
Convert Unix timestamps to dates and back, seconds or milliseconds, timezone-aware.
UTM Builder
Build UTM tracking links that merge cleanly with existing query params.
QR Code Generator
Generate QR codes from text or URLs, resize and download as PNG.
Image Compressor
Compress images locally in the browser with live size and ratio feedback.
Aspect Ratio Calculator
Derive missing dimensions from width, height or ratio, with common presets.
Color Converter
Convert between HEX, RGB and HSL with a live preview and one-click copy.
robots.txt Generator
Build common robots.txt rules and copy the result.
llms.txt Generator
Generate a clean llms.txt so LLMs can understand your site.
JSON-LD Schema Generator
Generate JSON-LD for Organization, WebSite, SoftwareApplication and more.
Markdown Editor & Preview
Split-pane Markdown editor with live preview, copy and download.
16 tools · all free, running locally in your browser