# John Leonardo (jdleo.me)

> Personal site of John Leonardo, Senior Software Engineer at Roblox. Home to 18 interactive AI and developer mini-apps plus a technical blog of AI/ML experiments.

John Leonardo — Senior Software Engineer specializing in distributed systems, high-scale architectures, and AI services. Experience at Roblox (OS), Amazon (Search Science) and IBM (iX). Expert in Java, Python, TypeScript, Rust, Go, and AWS.

All pages below exist as both HTML and clean Markdown.
Append `.md` to any page URL to get the Markdown version (e.g. https://jdleo.me/blog/tinysafe.md).
This file is the LLM-readable overview for the whole site.

## Apps

- [AI Chat](https://jdleo.me/apps/chat.md): Chat with cutting-edge AI models including GPT-5, Claude Sonnet 4, Grok 4, and more.
- [Chat w/ John](https://jdleo.me/apps/resume.md): This is an AI/LLM that knows everything about John's resume.
- [Resume Screen](https://jdleo.me/apps/screen.md): FOR RECRUITERS: Generate ungooglable screening questions from a resume.
- [AI Writing Detector](https://jdleo.me/apps/ai-writing-detector.md): Paste any text and get an estimated % chance it was AI-written, with reasons why.
- [LLM Serialization](https://jdleo.me/apps/serialization.md): Compare token efficiency across different serialization formats for LLMs.
- [Link Shortener](https://jdleo.me/apps/link-shortener.md): Create short links for your URLs with free analytics.
- [AI Diagram Generator](https://jdleo.me/apps/diagram.md): Use human language, and a perfect diagram will be generated for you.
- [Resume Parser](https://jdleo.me/apps/parser.md): Upload a resume and extract structured data with AI parsing.
- [Color Gamble](https://jdleo.me/apps/gamble.md): Test your luck with this simple but addictive color betting game.
- [Sort Viz](https://jdleo.me/apps/sort.md): Watch and learn how different sorting algorithms work in real-time.
- [Blockchain 101](https://jdleo.me/apps/blockchain.md): Interactive demo showing how blockchain technology actually works.
- [Hash Lab](https://jdleo.me/apps/hash.md): Convert text between different hash algorithms instantly.
- [Privacy Scanner](https://jdleo.me/apps/privacy.md): See what websites can learn about you through browser fingerprinting.
- [2026 California Tax Calculator](https://jdleo.me/apps/california-tax-calculator.md): Calculate your 2026 CA state income tax, federal tax, payroll taxes, and take-home pay.
- [Founder Dilution](https://jdleo.me/apps/dilution.md): Simulate startup fundraising rounds and see how your equity evolves from Seed to Exit.
- [AI Sentiment](https://jdleo.me/apps/sentiment.md): Track how public sentiment toward AI shifts week by week across 250 news articles.
- [PDF Chat (Embeddings)](https://jdleo.me/apps/rag.md): Upload any document and chat with it using AI semantic search.
- [Knowledge Graph](https://jdleo.me/apps/knowledge-graph.md): Construct and chat with dynamic knowledge graphs from any body of text.

## Blog

- [Thoughts on AI now in August 2026](https://jdleo.me/blog/thoughts-on-ai-aug-2026.md) (2026-08-28): My opinions on where we are, and where we go from here.
- [My Current AI Opinions](https://jdleo.me/blog/current-ai-opinions.md) (2026-03-15): My current thoughts on AI and how to be good at it.
- [TinySafe v3: How I Built a Near-SOTA Safety LLM for Under $100](https://jdleo.me/blog/tinysafe-v3.md) (2026-03-07): A 4B parameter model fine-tuned with QLoRA gets within 0.008 F1 of SOTA on ToxicChat, then hits a wall. Five versions, $100, and a lot of lessons about why 0.83 is so hard to break.
- [I Built TinySafe, a Safety Model that Beats 8B Guard Models with 71M Parameters for $37](https://jdleo.me/blog/tinysafe.md) (2026-02-28): Building a sub-2ms safety classifier that outperforms LlamaGuard, ShieldGemma, and every encoder-based model in its weight class.
- [Which AI Models Lean in Which Political Direction?](https://jdleo.me/blog/ai-political-compass.md) (2026-01-25): I asked the top LLMs 20 different political compass questions to figure out how left/right/libertarian/authoritarian they were.
- [Are Computer Science Majors "Cooked" because of AI?](https://jdleo.me/blog/are-computer-science-majors-cooked.md) (2025-09-22): A speculative deep dive on whether AI will augment or replace new software engineers.
- [I Trained AI on 70k Clash Royale Battles to Settle the Ultimate Debate: Does Your Deck Actually Matter?](https://jdleo.me/blog/clash-royale-ai-deck-prediction.md) (2025-09-14): Using machine learning on 70,000+ real battles from the Clash Royale API to definitively answer whether deck composition actually predicts victory, or if it's just skill and luck.
- [The Nutrition Prediction Benchmark: Testing LLMs on Google Cafeteria Menus](https://jdleo.me/blog/nutrition-benchmark.md) (2025-09-07): Testing large language models on their ability to predict accurate nutritional information from Google cafeteria dishes, revealing surprising insights about AI's understanding of food science.
- [The Semantic Diversity Benchmark: A New Way to Test AI Language Models](https://jdleo.me/blog/semantic-diversity-benchmark.md) (2025-08-31): A simple but powerful benchmark for testing AI language models by asking them to generate maximally semantically unrelated words, revealing surprising insights about model capabilities.
- [New Grad Job Search for Software Engineers](https://jdleo.me/blog/new-grad-swe-search.md) (2025-08-02): A quick guide for new grads looking to break into the software engineering industry, including networking tips, technical preparation advice, and insights into why the current job market is more challenging.
- [Transformers are Limited](https://jdleo.me/blog/transformers-are-limited.md) (2025-08-01): The transformer architecture is fundamentally limited for true reasoning.
- [Welcome to My Blog](https://jdleo.me/blog/first-post.md) (2025-06-09): Welcome to my blog!

## Optional

- [Sitemap](https://jdleo.me/sitemap.xml): full list of all pages
- [All apps as Markdown](https://jdleo.me/apps.md): index of the Apps section
- [All blog posts as Markdown](https://jdleo.me/blog.md): index of the Blog section