One File Tools

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

🏷️ Tags:
JSON Formatter

JSON Formatter

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

JSON & API Easy Live
Aspect Ratio Calculator

Aspect Ratio Calculator

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

CSS Tools 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
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
UUID Generator

UUID Generator

Generate random v4 UUIDs instantly, offline.

Developer Utilities Easy Live
No tools found matching your search.

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
5+
Tool Ideas
9
Categories
0 KB
npm install
100%
Browser-based

🌐 Web & SEO

🌐

Open Graph Inspector

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

🎨 CSS Tools

🎨

Aspect Ratio Calculator

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

🎨

Radii - Border Radius Generator

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

🔗 JSON & API

🔗

JSON Formatter

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

🛠️ Developer Utilities

🛠️

UUID Generator

Generate random v4 UUIDs instantly, offline.

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
🌐

Web & SEO

Meta tags, OG previews, sitemaps, and SEO utilities

1 tool
🖼️

Image Tools

Dimensions, converters, SVG, favicons, and metadata

0 tools
🌈

Color Tools

Pickers, contrast checkers, palettes, and converters

0 tools
🎨

CSS Tools

Shadows, grids, flexbox, gradients, and generators

2 tools
📝

Text & Content

Counters, converters, diffs, and Markdown preview

0 tools
🔗

JSON & API

Formatters, JWT decoders, URL encoders, and curl builders

1 tool
🛠️

Developer Utilities

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

1 tool
🌐

Browser & Network

User agents, viewport info, cookies, and headers

0 tools
♿

Accessibility

Contrast checkers, heading structure, ARIA references

0 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.
// Web & SEO
  • open-graph-inspector Analyze meta tags, social previews, and SEO metadata for any URL with actionable scores. MED
// CSS Tools
  • aspect-ratio-calculator Calculate and simplify aspect ratios instantly. Supports common presets and outputs decimal ratio and CSS padding-bottom values. EASY
  • border-radius-generator Visually create CSS border-radius values with live preview, presets, and copy-ready CSS output. EASY
// JSON & API
  • json-formatter Format, validate, and minify JSON locally in your browser. EASY
// Developer Utilities
  • uuid-generator Generate random v4 UUIDs instantly, offline. EASY
// Links

One File Tools

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

5+
Tool Ideas
9
Categories
5
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
🌐

Web & SEO

  • Open Graph Inspector
🖼️

Image Tools

    🌈

    Color Tools

      🎨

      CSS Tools

      • Aspect Ratio Calculator
      • Radii - Border Radius 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