Colophon

About This Site

This is a collection of small, single-purpose tools that run entirely in your browser. No data is sent to any server—everything happens client-side using JavaScript.

Inspired by Simon Willison's tools, this site is hosted on GitHub Pages as a collection of static HTML files.

Browser Tools

• JSON Formatter - Format and validate JSON
• Base64 Encoder/Decoder - Encode/decode Base64
• 529 College Savings Projector - Project college savings
• Time-Money Trade-Off Calculator - Calculate effective hourly rate for outsourcing decisions
• Slack Text Cleaner - Clean up Slack conversations into Markdown
• Investment Growth Calculator - Visualize growth, advisor fee costs, and Monte Carlo outcomes
• Baby Food Tracker - Track baby's solid food introduction with AAP/Solid Starts guidelines
• Mortgage Comparison Calculator - Compare up to 4 mortgage scenarios with closing costs, refinance mode, and OCR upload

Python Scripts

Command-line tools that can be run via uv run directly from URLs, inspired by Simon Willison's Python scripts.

• PR Reviewer - AI-powered GitHub PR code review using Claude Code

Technical Details

Each tool is a standalone HTML file with embedded JavaScript and CSS. This approach means:

• No build process required
• Easy to add new tools (just add a new .html file)
• Works offline (after first load)
• No build step — external libraries via CDN are fine
• Fast and simple

Development

Repository: github.com/striglia/tools-locallyoptimal
Built with: Vanilla HTML, CSS, and JavaScript
Hosted on: GitHub Pages
Main site: locallyoptimal.com

Adding New Tools

To add a new tool:

1. Create a new tool-name.html file
2. Add it to index.html
3. Update this colophon if desired
4. Commit and push—GitHub Pages will deploy automatically