A collection of handy developer utilities — all running in your browser.
Find the differences between two blocks of text.
Render Markdown to HTML with live preview.
Base64, URL and other common encodings.
Encode files/images to Base64 and back.
Decode a JWT header, payload and claims.
Convert dates between formats and time zones.
Calculate the difference between two dates.
Explain a cron expression and preview next runs.
Generate unique identifiers (UUID v4).
Create QR codes from text or URLs.
Scan QR codes with your camera or an image.
Beautify, minify and validate JSON.
Compare two JSON documents structurally.
Convert between CSV and JSON both ways.
Pretty-print and validate XML.
Format and beautify SQL queries.
Compress, resize and convert images (PNG/JPG/WebP).
Convert between binary, octal, decimal and hex.
Pick colors and convert HEX ↔ RGB ↔ HSL.
Convert length, weight, temperature and more.
Tổng hợp ngữ pháp TOEIC theo từng mốc điểm, kèm ví dụ & mẹo.
Ngữ pháp JLPT N5 → N3: định nghĩa, cấu trúc, ví dụ Nhật–Việt & mẹo.
Ngữ pháp TOPIK cấp 1 → 3: định nghĩa, cấu trúc, ví dụ Hàn–Việt & mẹo.