One File Tools

Developer tools, one file each. No build step. No dependencies. No frameworks.

🏷️ Tags:
Aspect Ratio Calculator

Aspect Ratio Calculator

Calculate and simplify aspect ratios instantly. Supports common presets and outputs decimal ratio and CSS padding-bottom values.

Image Tools Easy Live
Box Shadow Generator

Box Shadow Generator

Design CSS box shadows visually with live preview, presets, and copy-ready output.

CSS Tools Easy Live
Clip Path Generator

Clip Path Generator

Visually create complex CSS clip-path shapes and instantly copy the generated code.

CSS Tools Medium Live
Color Palette Extractor

Color Palette Extractor

Extract dominant colors and generate beautiful palettes directly from images in your browser.

Image Tools Medium Live
CSS Grid Generator

CSS Grid Generator

Build CSS Grid layouts visually with configurable columns, rows, gap, and sizing options.

CSS Tools Medium Live
Favicon Generator

Favicon Generator

Generate a complete favicon pack and integration tags from any image, offline.

Developer Utilities Easy Live
GitHub Token Validator (Terminal)

GitHub Token Validator (Terminal)

Validate GitHub Personal Access Tokens with a terminal-style UI that displays user identity and scopes.

Developer Utilities Easy Live
GitHub Token Validator Plain

GitHub Token Validator Plain

Validate GitHub Personal Access Tokens with a clean, straightforward interface.

Developer Utilities Easy Live
GitHub Token Validator Retro

GitHub Token Validator Retro

Validate GitHub Personal Access Tokens with a retro terminal themed interface.

Developer Utilities Easy Live
Glassmorphism Generator

Glassmorphism Generator

Generate sleek, frosted-glass UI effects for your components.

CSS Tools Easy Live
JSON Formatter

JSON Formatter

Format, validate, and minify JSON locally in your browser.

JSON & API Easy Live
JWT Decoder

JWT Decoder

Decode and inspect JSON Web Tokens — header, payload, claims, and expiry — entirely in your browser.

JSON & API Easy Live
Open Graph Inspector

Open Graph Inspector

Analyze meta tags, social previews, and SEO metadata for any URL with actionable scores.

Web & SEO Medium Live
Palette Generator

Palette Generator

Generate unique, collision-free variation color schemes based on color theory metrics, offline.

Color Tools Medium Live
Radii - Border Radius Generator

Radii - Border Radius Generator

Visually create CSS border-radius values with live preview, presets, and copy-ready CSS output.

CSS Tools Easy Live
Twitter / X Card Preview

Twitter / X Card Preview

Preview how Twitter/X cards appear with live updates for Summary and Summary Large Image layouts.

Web & SEO Easy Live
UUID Generator

UUID Generator

Generate random v4 UUIDs instantly, offline.

Developer Utilities Easy Live

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One tool.
One file.
Open and use.

A collection of useful developer tools, each built as a single, self-contained HTML file. No build step. No dependencies. No frameworks.

Browse Tools View on GitHub Contribute
17+
Tool Ideas
9
Categories
0 KB
npm install
100%
Browser-based

🌈 Color Tools

🌈

Palette Generator

Generate unique, collision-free variation color schemes based on color theory metrics, offline.

🎨 CSS Tools

🎨

Box Shadow Generator

Design CSS box shadows visually with live preview, presets, and copy-ready output.

🎨

Clip Path Generator

Visually create complex CSS clip-path shapes and instantly copy the generated code.

🎨

CSS Grid Generator

Build CSS Grid layouts visually with configurable columns, rows, gap, and sizing options.

🎨

Glassmorphism Generator

Generate sleek, frosted-glass UI effects for your components.

🎨

Radii - Border Radius Generator

Visually create CSS border-radius values with live preview, presets, and copy-ready CSS output.

🛠️ Developer Utilities

🛠️

Favicon Generator

Generate a complete favicon pack and integration tags from any image, offline.

🛠️

GitHub Token Validator (Terminal)

Validate GitHub Personal Access Tokens with a terminal-style UI that displays user identity and scopes.

🛠️

GitHub Token Validator Plain

Validate GitHub Personal Access Tokens with a clean, straightforward interface.

🛠️

GitHub Token Validator Retro

Validate GitHub Personal Access Tokens with a retro terminal themed interface.

🛠️

UUID Generator

Generate random v4 UUIDs instantly, offline.

🖼️ Image Tools

🖼️

Aspect Ratio Calculator

Calculate and simplify aspect ratios instantly. Supports common presets and outputs decimal ratio and CSS padding-bottom values.

🖼️

Color Palette Extractor

Extract dominant colors and generate beautiful palettes directly from images in your browser.

🔗 JSON & API

🔗

JSON Formatter

Format, validate, and minify JSON locally in your browser.

🔗

JWT Decoder

Decode and inspect JSON Web Tokens — header, payload, claims, and expiry — entirely in your browser.

🌐 Web & SEO

🌐

Open Graph Inspector

Analyze meta tags, social previews, and SEO metadata for any URL with actionable scores.

🌐

Twitter / X Card Preview

Preview how Twitter/X cards appear with live updates for Summary and Summary Large Image layouts.

One File Tools

Try a tool right here. Every tool is a single HTML file you can download and use anywhere.

json-formatter.html 
Formatted output will appear here...
🎓 Part of Social Summer of Code — Easy: 20 pts · Medium: 30 pts · Leaderboard
♿

Accessibility

Contrast checkers, heading structure, ARIA references

0 tools
🌐

Browser & Network

User agents, viewport info, cookies, and headers

0 tools
🌈

Color Tools

Pickers, contrast checkers, palettes, and converters

1 tool
🎨

CSS Tools

Shadows, grids, flexbox, gradients, and generators

5 tools
🛠️

Developer Utilities

UUIDs, hashes, regex, cron, passwords, and QR codes

5 tools
🖼️

Image Tools

Dimensions, converters, SVG, favicons, and metadata

2 tools
🔗

JSON & API

Formatters, JWT decoders, URL encoders, and curl builders

2 tools
📝

Text & Content

Counters, converters, diffs, and Markdown preview

0 tools
🌐

Web & SEO

Meta tags, OG previews, sitemaps, and SEO utilities

2 tools 
  ___  _  _ ___   ___ ___ _    ___   _____ ___   ___  _    ___
 / _ \| \| | __| | __|_ _| |  | __| |_   _/ _ \ / _ \| |  / __|
| (_) | .` | _|  | _| | || |__| _|    | || (_) | (_) | |__\__ \
 \___/|_|\_|___| |_| |___|____|___|   |_| \___/ \___/|____|___/
~/one-file-tools $

One File Tools

Developer tools, one file each. Zero dependencies.

$ open tools/json-formatter.html

$ # That's it. No npm. No build. No server.
// Color Tools
  • palette-generator Generate unique, collision-free variation color schemes based on color theory metrics, offline. MED
// CSS Tools
  • box-shadow-generator Design CSS box shadows visually with live preview, presets, and copy-ready output. EASY
  • clip-path-generator Visually create complex CSS clip-path shapes and instantly copy the generated code. MED
  • css-grid-generator Build CSS Grid layouts visually with configurable columns, rows, gap, and sizing options. MED
  • glassmorphism-generator Generate sleek, frosted-glass UI effects for your components. EASY
  • border-radius-generator Visually create CSS border-radius values with live preview, presets, and copy-ready CSS output. EASY
// Developer Utilities
  • favicon-generator Generate a complete favicon pack and integration tags from any image, offline. EASY
  • github-token-validator-terminal Validate GitHub Personal Access Tokens with a terminal-style UI that displays user identity and scopes. EASY
  • github-token-validator-plain Validate GitHub Personal Access Tokens with a clean, straightforward interface. EASY
  • github-token-validator-retro Validate GitHub Personal Access Tokens with a retro terminal themed interface. EASY
  • uuid-generator Generate random v4 UUIDs instantly, offline. EASY
// Image Tools
  • aspect-ratio-calculator Calculate and simplify aspect ratios instantly. Supports common presets and outputs decimal ratio and CSS padding-bottom values. EASY
  • color-palette-extractor Extract dominant colors and generate beautiful palettes directly from images in your browser. MED
// JSON & API
  • json-formatter Format, validate, and minify JSON locally in your browser. EASY
  • jwt-decoder Decode and inspect JSON Web Tokens — header, payload, claims, and expiry — entirely in your browser. EASY
// Web & SEO
  • open-graph-inspector Analyze meta tags, social previews, and SEO metadata for any URL with actionable scores. MED
  • twitter-x-card-preview Preview how Twitter/X cards appear with live updates for Summary and Summary Large Image layouts. EASY
// Links

One File Tools

Developer tools, one file each. No build step. No dependencies. No frameworks.

17+
Tool Ideas
9
Categories
17
Live Tools
0
Dependencies
💡

Philosophy

One file. Each tool is a single .html file.
Zero build. No npm install, no bundler, no server.
Browser only. Runs entirely client-side.
Open source. Unlicense. Do what you want.

Start Contributing

Pick a tool, build it in a single HTML file, and submit a PR.

GitHub Contributing Guide
♿

Accessibility

    🌐

    Browser & Network

      🌈

      Color Tools

      • Palette Generator
      🎨

      CSS Tools

      • Box Shadow Generator
      • Clip Path Generator
      • CSS Grid Generator
      • Glassmorphism Generator
      🎓

      SSoC (Social Summer of Code)

      This project is part of Social Summer of Code. Pick an Easy (20 pts) or Medium (30 pts) issue, build a tool, and earn contribution points. Learn more · Leaderboard