A collection of 99 tiny, self-contained browser tools: each one a single HTML file with no external dependencies.
No frameworks. No CDNs. No build steps. Just open a file and use it.
Every tool in this gallery is a single .html file. All the CSS and JavaScript live inline. You can open any tool directly in a browser, copy it to your desktop, email it to someone; it just works.
The gallery site is a lightweight wrapper that indexes every tool and lets you search, filter by tag, and use them inline.
| Tool | Description |
|---|---|
| JSON Formatter | Pretty-print and validate JSON with syntax highlighting |
| Regex Tester | Test regular expressions against sample text with live match highlighting |
| Base64 Encode/Decode | Convert text to and from base64 |
| Timestamp Converter | Unix timestamps to human-readable dates and back |
| Diff Checker | Side-by-side text comparison with change highlights |
| CSV to JSON | Convert between CSV and JSON formats |
| Hash Generator | SHA-256, SHA-1, and MD5 hashes via Web Crypto API |
| URL Encode/Decode | Encode and decode URL components |
| JWT Decoder | Decode JWT tokens and check expiration |
| HTML Entity Encoder | Convert special characters to and from HTML entities |
| Cron Expression Explainer | Translate cron expressions to plain English |
| HTTP Status Code Reference | Searchable list of HTTP status codes |
| SQL Formatter | Indent and highlight SQL queries |
| Mock Data Generator | Generate random JSON data from a schema |
| Chmod Calculator | Toggle permissions, get numeric and symbolic chmod |
| Tool | Description |
|---|---|
| Color Palette Generator | Generate complementary, analogous, and triadic palettes |
| CSS Gradient Builder | Visual gradient editor with CSS output |
| Contrast Checker | Check WCAG AA/AAA color contrast compliance |
| Placeholder Image Generator | Create colored placeholder images with custom dimensions |
| Box Shadow Generator | Visual box-shadow editor with layering |
| Flexbox Playground | Interactive flexbox property editor |
| CSS Grid Generator | Build grid layouts with visual controls |
| Border Radius Generator | Per-corner border radius editor |
| Font Pairing Preview | Preview text in font combinations |
| SVG Path Visualizer | Render and inspect SVG path data |
| CSS Animation Builder | Keyframe editor with timing preview |
| Glass Morphism Generator | Frosted glass CSS effect generator |
| Color Blindness Simulator | Preview colors under different types of color blindness |
| Favicon Generator | Draw a 16x16 favicon and export |
| Tailwind Color Reference | Browse the Tailwind color palette |
| Tool | Description |
|---|---|
| Word and Character Counter | Counts, reading time, and text statistics |
| Markdown Table Generator | Visual grid editor for markdown tables |
| Lorem Ipsum Generator | Generate placeholder text |
| Case Converter | Convert between camelCase, snake_case, kebab-case, and more |
| Slug Generator | Turn text into URL-friendly slugs |
| Markdown Preview | Split-pane markdown editor and preview |
| Find and Replace | Regex-capable find and replace |
| Text Sorter | Sort, shuffle, and deduplicate lines |
| Whitespace Cleaner | Trim, collapse, and normalize whitespace |
| Placeholder Name Generator | Generate random names, emails, and addresses |
| Sentence Diagram | Basic subject/verb/object breakdown |
| Reading Level Analyzer | Flesch-Kincaid readability scoring |
| Tool | Description |
|---|---|
| Aspect Ratio Calculator | Calculate proportional dimensions |
| Percentage Calculator | Common percentage operations |
| Byte Size Converter | Convert between data size units |
| Subnet Calculator | CIDR to network range and host count |
| Tip Calculator | Split bills with tip |
| Number Base Converter | Binary, octal, decimal, hex conversion |
| Loan Payment Calculator | Monthly payments and amortization |
| Statistics Calculator | Mean, median, mode, std dev, quartiles |
| Matrix Calculator | Add, multiply, transpose, determinant |
| Roman Numeral Converter | Decimal to Roman numerals and back |
| Tool | Description |
|---|---|
| Password Generator | Configurable random passwords with strength meter |
| Pomodoro Timer | Work/break timer with audio chime |
| Unit Converter | Length, weight, temperature, volume, speed |
| QR Code Generator | Generate QR codes from text or URLs |
| Cooking Converter | Metric and imperial baking measurements |
| Stopwatch | Start, stop, lap, reset |
| Countdown Timer | Set a duration and count down |
| World Clock | Current time across multiple timezones |
| Age Calculator | Exact age from a birthdate |
| Screen Ruler | Measure pixel distances on screen |
| Habit Tracker | Weekly checkbox grid |
| Daily Planner | Time-blocked day view |
| Tool | Description |
|---|---|
| .gitignore Generator | Select languages and frameworks, get a .gitignore |
| robots.txt Generator | Build robots.txt with user-agent rules |
| Meta Tag Generator | Generate SEO and social meta tags |
| README Template | Scaffold a project README |
| .env Template Generator | Define key-value pairs, get a .env file |
| Changelog Generator | Add entries by version, get Keep a Changelog format |
| Package.json Scaffolder | Fill in fields, get valid package.json |
| Tool | Description |
|---|---|
| Privacy Policy Template | Fill in blanks, get a basic privacy policy |
| Password Strength Checker | Real-time strength analysis |
| CORS Header Tester | See what CORS headers the browser sends |
| CSP Header Builder | Visual Content-Security-Policy editor |
| TOTP Code Generator | Rolling 6-digit codes from a secret key |
| SSL Certificate Decoder | Decode PEM certificates |
| Data Size Estimator | Estimate storage for a dataset |
| UUID Generator | Generate and copy v4 UUIDs |
| Tool | Description |
|---|---|
| Pixel Art Editor | Grid-based pixel art with PNG export |
| Dice Roller | Roll any combination of polyhedral dice |
| ASCII Art Generator | Convert text to block ASCII characters |
| Drum Machine | 8-step sequencer with Web Audio |
| Spirograph | Animated spirograph with adjustable parameters |
| Generative Art Cards | Random geometric art compositions |
| Reaction Time Tester | Test your reaction speed |
| Typing Speed Test | WPM and accuracy on random text |
| Memory Card Game | Flip emoji card pairs |
| Snake Game | Classic snake with increasing speed |
| Conway's Game of Life | Cellular automaton sandbox |
| Maze Generator | Generate and solve random mazes |
| Optical Illusion Gallery | Classic illusions in CSS and canvas |
| Music Scale Explorer | Piano keyboard with scale highlighting |
| Etch-a-Sketch | Draw with keys or mouse, shake to clear |
| Color Mixing Lab | Subtractive color mixing on canvas |
| Star Map | Seasonal constellation viewer |
| Gradient Wallpaper Maker | Generate and export gradient wallpapers |
| Mini Synth | Playable keyboard with waveform and envelope controls |
| Lava Lamp | Animated blob simulation |
Each tool has a metadata comment at the top of the file:
<!--
name: Tool Name
description: What it does
author: github-username
tags: tag1, tag2
-->A build script reads every .html file in tools/, extracts the metadata, and generates manifest.json. The gallery page reads that manifest to render the searchable grid. A GitHub Action runs this automatically on every push.
See CONTRIBUTING.md. The short version: add a single HTML file to tools/, fill in the metadata comment, open a PR.
This project will be released under the MIT License.