Tools
ASCII Art
Turn text into ASCII character art
Codec
Base64 / URL / Case / 进制 编解码工具
BMI Calculator
Calculate your body mass index
Color Tool
取色器、调色板、渐变与对比度等
Time Tool
倒计时、时区、时间戳、日期计算
Cron Expression Generator
Visually generate Cron scheduling expressions
Flexbox/Grid Generator
Visualize CSS Flexbox and Grid layouts
What to Eat Today
Not sure what to eat? Give it a spin
GIF Maker
Combine multiple images into an animated GIF
Git Command Generator
A quick reference for common Git commands
Image Tool
对比、拼接、水印、转 Base64 等
Random Image
Anime-ish pictures, you know
IP Address Lookup
Look up the geographic location of an IP address
Format Converter
JSON / CSV / XML / YAML / Markdown 互转
JWT Parser
Parse the Header and Payload of a JWT token
Lorem Image
Generate placeholder images by size
Morse Code
Convert text to and from Morse code
Mortgage Calculator
Equal-installment / equal-principal mortgage calculation
Pixel Art Editor
A pixel art drawing board
Pomodoro Timer
Focus on work, rest efficiently
QR Code Generator
Turn text into a QR code
Random Tool
随机抽取、概率模拟
Random Quotes
Something random (from the Hitokoto API)
Regex Tester
Write regex and see live match highlighting
Text Tool
去重、对比、反转、词频统计
Bitwise Calculator
Compute bitwise AND/OR/XOR/NOT/shift on two integers, shown in decimal, binary and hex.
Breathing Exercise
Follow the expanding circle for a calm breathing routine.
RPG Character Generator
Roll a random RPG character with name, race, class and stats.
Compound Interest Calculator
Project future value with monthly compounding and contributions.
20-20-20 Eye Rest
Reminds you to rest your eyes every 20 minutes.
Plot Tool
函数、波形、频谱、傅里叶
GraphQL Query Builder
Build GraphQL queries from fields and arguments.
Logic Gate Playground
Toggle two inputs and watch the live output of AND/OR/NOT/XOR/NAND/NOR gates.
Fractal
曼德博、朱利亚、L 系统等分形可视化
Numeral
进制转换、中文数字、罗马数字
Nutrition Calculator
Estimate daily water, TDEE and macro needs from your body data.
Periodic Table
Browse all 118 chemical elements; click any element to view its details.
Semver Calculator
Compare and bump semantic versions.
SQL Formatter
Pretty-print and format SQL queries.
Truth Table Generator
Build the full truth table for a boolean expression with variables, supporting and/or/not/xor/implies.
Word Cloud Generator
Generate a word cloud from input text
Lorem Ipsum
Generate Lorem Ipsum placeholder text by paragraphs, sentences or words.
Password Generator
Generate secure random passwords with customizable options
Unit Converter
Convert between length, weight and temperature units
UUID Generator
Generate one or many UUID v4 identifiers
Hash Generator
Generate MD5 and SHA-256 hashes for any text instantly.
JSONPath Tester
Test JSONPath expressions against JSON
JSON Schema
Generate or validate JSON Schema
WebSocket Console
Debug WebSocket connections in-browser
REST Client
A mini HTTP request client
cURL ⇄ Code
Parse cURL and generate Python/JS/Go
Docker ⇄ Compose
Convert docker run to docker-compose
Commit Generator
Build Conventional Commits messages
ID Generator
Generate NanoID and Snowflake IDs
URL Params
Parse and rebuild URL query params
Barcode Generator
Generate Code128 barcodes
CSS Generator
Generate shadow / border / radius CSS
Grid Generator
Visualize and generate CSS grid layouts
Box Shadow
Interactive box-shadow generator
Favicon Generator
Generate multi-size favicons
OG Image
Generate social share (OG) images
Emoji Dictionary
Search and copy emojis
Unicode Table
Browse Unicode code points
Keycode Viewer
Show key code info on keypress
Cron Next Run
Predict next cron execution time
Lint Check
Basic style checks by language
API Mock Generator
Generate mock data from JSON schema
Loan Calculator
Mortgage / car loan monthly payment
Compound Interest
Compare savings with recurring deposits
Income Tax (CN)
Estimate individual income tax
Calorie Burn
Estimate calories burned by activity
Ovulation Tracker
Estimate fertile window
BAC Estimator
Estimate blood alcohol concentration
Fish Tank
Tank volume and water change
Renovation Estimator
Estimate paint / flooring material
Ingredient Converter
Cups to grams / ml
Scientific Calculator
Functions and constants
Math Tool
复数、矩阵、向量、大数、质数
IEEE 754 Viewer
Visualize float32 bit layout
Gacha Simulator
Simulate pulls with pity
Permutation / Combination
Compute P(n,k) and C(n,k)
Z-Table
Standard normal distribution query
T-Test / CI
One-sample t-test and p-value
Linear Regression
Fit a line to scatter points
Nine-Grid
Split an image into 3x3 for moments
Texture Generator
Noise / wave textures
Kaleidoscope
Draw symmetric kaleidoscope art
2D Simulation
单摆、洛伦兹、引力沙盘、随机游走
3D Terrain
Perlin-noise heightmap terrain
Constellation
Procedural star map generator
SWOT Analysis
Four-quadrant SWOT editor
Buffon's Needle
Estimate π from needles crossing parallel lines.
Dynamic Programming Visualizer
0/1 Knapsack and Longest Increasing Subsequence DP tables.
Equation Balancer
Balance simple A + B -> C equations by atom conservation.
Gaussian Sampler
Sample from a normal distribution and view the histogram.
Huffman Tree
Build a Huffman tree and derive prefix codes from text.
Markov Chain Text
Generate a sequence from a custom transition matrix.
Mole Calculator
Molar mass and mass-to-moles for simple formulas.
Monte Carlo π
Estimate π by throwing darts into a circle inside a square.
Music Tool
八音盒、节拍器、合成器、简谱
Neural Net Visualizer
A small feed-forward net with sigmoid activations you can poke.
Red-Black / AVL Rotation
Insert nodes and perform left/right rotations to see tree balance.
Search Visualizer
Step through binary search, DFS and BFS on a graph/array.
Shortest Path
Dijkstra / A* on a weighted grid with obstacles.
Sorting Visualizer
Watch bubble / quick / merge sort animate step by step.
Ulam Spiral
Primes highlighted along a square spiral — diagonal patterns emerge.
Union-Find
Disjoint-set union with path compression and union by rank.
White Noise Generator
White / pink / brown noise with adjustable volume.
Calculators
Tip split, currency conversion and fish-tank volume calculators.
Chart Toolkit
Bar/pie/line charts, decision matrix, A/B sample size, radar, heatmap, boxplot, candlestick and bubble charts — all rendered with pure SVG.
CSS Toolkit
Convert HTML/JSX, build clip-path, glassmorphism and neumorphism styles.
DevOps Cheat Sheet
Cheat sheets for shell, vim, tmux, systemd, Docker, K8s, nginx, git and more.
Dev Toolkit
JSON formatter, LOC counter, TODO extractor, JSDoc comment generator, complexity estimator and code card.
Divination Toolkit
Lot drawing, I Ching coin casting, daily tarot draw, Guandi lots, coin-flip decisions, dream dictionary and a fun fortune teller.
Finance Toolkit
DCA projection, Black-Scholes option pricing, installment comparison, 50/30/20 budget, AA split, FIRE calculator, inflation purchasing power and retirement estimate.
Generators
Generate .gitignore, LICENSE and README templates in one place.
Learn Toolkit
Flashcards, kana chart, stroke counts, idiom chain, poem fill-in and brain teasers.
Life Toolkit
Love match, horoscope, coin decision, habit/water/ledger/todo trackers, vCard/iCal, username/avatar/placeholder generators and more.
Misc Toolkit
Charset/encoding viewer, HTML entity, JS sandbox, CSS unit converter, selector tester, markdown table, TOC, JSON query and viewport inspector.
Science Toolkit
Karnaugh map simplifier, physics constants, resistor color codes, binary logic and base conversion.
Security Reference
Quick reference for XSS/SQLi payloads, HTTP status, OWASP, CORS, DNS, ports and more.
Psych Test Toolkit
MBTI, Big Five, Holland RIASEC, EQ, GAD-7 anxiety, PHQ-9 depression, stress, DISC, left/right brain and Enneagram self-assessments.
Algorithm Visualizer
Interactive BST, AVL, B-tree and skip-list visualizers rendered with pure SVG.
DP Algorithm Visualizer
0/1 knapsack, LCS, LIS and minimum-coin DP tables with backtracking.
Algorithm Graph Visualizer
DFS, BFS, Kruskal MST, Dijkstra shortest path and Ford-Fulkerson max flow, all visualized on a fixed graph with pure SVG.
Eco Toolkit
Household CO2 estimate, recycling bin lookup, water usage and tree-offset calculator.
Fitness Toolkit
One-rep max (Epley), US Navy body fat, MET calorie burn, running pace and barbell plate calculator.
Food Toolkit
Harris-Benedict daily calories, macro split, recipe scaler and cooking unit converter.
Geo Toolkit
Great-circle distance, DMS conversion, bearing and timezone-offset helpers — all pure math.
History Toolkit
Build timelines, look up Chinese dynasties by year, convert to sexagenary (Ganzhi) cycles and compute age.
Language Toolkit
Palindrome & anagram detection, Caesar cipher, Morse code conversion and word counting.
Life Event Toolkit
Live countdowns, exact age, life-stage timeline and Chinese zodiac & horoscope lookup.
Meditation Toolkit
Breathing pacer, meditation timer and gratitude journal — a calm space to relax.
Pet Toolkit
Dog/cat age conversion, daily feeding estimate and random pet name generator.
Renovation Toolkit
Paint liters, flooring quantity, budget split and multi-room area calculators.
Directory & List Diff
Compare two directory trees or plain lists and find added, removed and common entries.
Env Parser
Parse, diff and scaffold .env files.
Astronomy Toolkit
Sun/moon positions, moon phase, eclipses, planets, meteor showers, aurora probability.
Biology Toolkit
DNA transcription/translation, codon table, organelle/anatomy atlas, blood-type genetics, pedigree, half-life.
Blockchain Demo
Demos of addresses/keypairs, tx structure, Merkle tree, PoW, block explorer (demo quality).
Chemistry Toolkit
pH, buffer, molarity dilution, redox balancing and Lewis structures.
Crypto Visualizer
Visual demo of Diffie-Hellman key exchange and elliptic-curve point addition.
Ecosystem Sim
Simulate species/resource balance in a terrarium.
FX Toolkit
Canvas particle/filter effects and Web Audio sound effects (no 3D/AR/WebGL).
Idle Family
Restaurant management and factory supply-chain idle games.
Simulation Toolkit
Lightweight simulations: city, UN, election, startup, life, lottery, auction, games.
Writer Toolkit
Name generator, worldbuilding/character cards, outline, word count, writing sprint and writing exercises.