CloudSea Toolbox
Useful and responsive web tools for everyday work and life.
JSON Formatter
Paste JSON to format, validate and prettify.
JSON → TypeScript
Convert JSON to TypeScript interface definitions instantly.
JWT Decoder
Decode and inspect JWT header, payload, and expiry status.
List Diff
Compare two lists and highlight added, removed, and common items.
UUID Generator
Generate v4 UUIDs in bulk, copy individually or all at once.
CRON Expression Generator
Visually build CRON expressions and preview next execution times.
SQL Formatter
Beautify or compress SQL queries with keyword uppercasing.
Regex Tester
Test regex patterns with real-time match highlighting.
Hash Generator
Calculate MD5, SHA-1, SHA-256, SHA-512 hashes — 100% client-side.
IP Info
Look up your IP address and geolocation information.
User Agent Parser
Parse User Agent strings to detect browser, OS, and device.
Diff Viewer
Compare two texts side-by-side and highlight differences.
HTTP Status Codes
Browse and search all HTTP status codes with descriptions.
Chmod Calculator
Calculate Unix file permissions in symbolic and numeric notation.
JSON Path Finder
Navigate JSON and find paths to any value.
Encoding Detector
Detect text encoding and convert between UTF-8, ASCII, and more.
Token Counter
Estimate token counts for GPT, Claude, and other LLM models.
Prompt Template
Build prompt templates with {{variables}}, fill values, and copy.
URL Parameter Parser
Paste a URL and instantly parse query parameters as table and JSON.
HTML Entity Encoder
Encode and decode HTML entities like & < > etc.
URL Encoder/Decoder
Encode or decode URL components with percent-encoding.
CSS Minifier
Minify or beautify CSS code instantly.
JS Minifier
Minify or beautify JavaScript code in the browser.
HTML Formatter
Format and indent HTML markup for readability.
CSS Unit Converter
Convert between px, rem, em, pt, and % units.
Box Shadow Generator
Visually generate CSS box-shadow with live preview.
Gradient Generator
Create CSS linear and radial gradients visually.
Meta Tag Generator
Generate HTML meta tags for SEO and social sharing.
Placeholder Image
Generate placeholder images with custom size, color, and text.
Markdown → HTML
Convert Markdown text to clean HTML output.
Case Converter
Convert text between camelCase, snake_case, kebab-case, and more.
Word Counter
Count words, characters, sentences, and estimate reading time.
Markdown Editor
Write Markdown with a live side-by-side HTML preview.
Lorem Ipsum Generator
Generate placeholder text in Latin or Traditional Chinese for design mockups.
Emoji Picker & Search
Browse, search, and copy emojis with Unicode codepoint details.
Number to Words
Convert numbers to their English or Chinese word form.
YAML / JSON Converter
Convert between YAML and JSON in both directions.
Timestamp Converter
Convert between Unix timestamps and human-readable dates.
Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 back to plain text.
Unicode Converter
Convert text ↔ Unicode code points and HTML entities.
QR Code Generator
Convert any URL or text into a downloadable QR code image.
Color Converter
Convert colors between HEX, RGB, and HSL with a visual palette.
Number Base Converter
Convert numbers between binary, octal, decimal, hex, and custom bases.
JSON ↔ CSV Converter
Convert between JSON arrays and CSV with nested object flattening.
Image → Base64
Convert images to Base64 data URIs for embedding.
Roman Numeral
Convert between Arabic numbers and Roman numerals.
Temperature Converter
Convert between Celsius, Fahrenheit, and Kelvin.
Unit Converter
Convert length, weight, volume, and area units.
Aspect Ratio Calculator
Calculate and convert aspect ratios for images and video.
Percentage Calculator
Calculate percentages, increases, decreases, and ratios.
Discount Calculator
Calculate sale prices, savings, and discount percentages.
Tip Calculator
Calculate tip amount and split bills among diners.
BMI Calculator
Calculate Body Mass Index with health category.
Age Calculator
Calculate exact age in years, months, and days.
Date Difference
Calculate the difference between two dates.
Mortgage Calculator
Calculate monthly mortgage payments and total interest.
Compound Interest
Calculate compound interest growth over time.
Grade Calculator
Calculate weighted GPA and course grades.
Unit Price Compare
Compare unit prices to find the best deal.
Expense Splitter
Split expenses among friends with uneven shares.
Image Compressor
Compress and convert images to WebP/JPEG/PNG — all in-browser.
SVG → PNG/JPG
Convert SVG code or files to downloadable PNG/JPG images.
Image Crop & Resize
Crop and resize images with a visual selection tool.
Color Blindness Sim
Simulate how colors appear with different types of color blindness.
Drawing Board
Simple whiteboard for freehand drawing and sketching.
Screen Ruler
Measure pixel distances on your screen.
Digital Clock
Large real-time clock with full-screen mode.
Time Zone Converter
Convert times between world time zones.
World Clock
View current time in multiple cities around the world.
Stopwatch
Precise stopwatch with lap times and history.
Countdown Timer
Set a countdown timer with alarm notification.
Pomodoro Timer
Focus timer with work, short break, and long break intervals.
Speech Timer
Timer for speeches and presentations with alerts.
Metronome
Adjustable BPM metronome with visual beat indicator.
Custom Roulette
Enter options and spin to pick one randomly.
Scoreboard
Track and control scores for two players or teams.
Gomoku
Classic Five-in-a-Row game. Play against a friend or challenge the AI.
Rubik's Cube
Interactive 3D Rubik's Cube. Rotate faces, shuffle, and solve.
Tic-Tac-Toe
Classic Tic-Tac-Toe — play against a friend or challenge the AI.
Typing Practice
Minimalist typing speed test with WPM and accuracy tracking.
Minesweeper
Classic Minesweeper — three difficulties with timer and flags.
2048
Slide numbered tiles to merge and reach 2048.
Snake
Classic Snake game — eat food and grow longer.
Memory Game
Flip cards to find matching pairs — test your memory.
Sudoku
Play Sudoku with multiple difficulty levels and hints.
Rock Paper Scissors
Play Rock Paper Scissors against the computer.
Hangman
Guess the word one letter at a time — classic word game.
Connect Four
Drop discs to connect four in a row — play vs friend or AI.
Tetris
Classic Tetris — stack falling blocks and clear lines.
Random Number
Generate random numbers within a custom range.
Coin Flip
Flip a virtual coin with animation and statistics.
Dice Roller
Roll virtual dice with customizable number and sides.
Password Generator
Create strong passwords with configurable rules.
Hiragana Flashcards
Quiz yourself on all 46 hiragana characters with instant feedback.
Katakana Flashcards
Quiz yourself on all 46 katakana characters with instant feedback.
Breathing Exercise
Guided breathing exercise with visual animation.
Virtual Piano
Play piano with your keyboard — two octaves of keys.
Noise Generator
Generate white, pink, or brown noise for focus or sleep.
Flashcard Maker
Create custom flashcards for study and memorization.
Habit Tracker
Track daily habits with streaks and completion stats.
Kanban Board
Simple drag-and-drop Kanban board for task management.