https://joshfonseca.com Technical writing on AI, engineering, and product en-us https://joshfonseca.com/blogs/accelerating-grokking.html Letting a model overfit first, then applying Frobenius norm regularization, achieves grokking in roughly half the steps of Grokfast on modular arithmetic. Fri, 24 Jan 2026 12:00:00 GMT https://joshfonseca.com/blogs/accelerating-grokking.html https://joshfonseca.com/blogs/how-to-know-whats-worth-learning.html In a world drowning in information, how do we distinguish signal from noise? The answer isn't choosing between classics and cutting-edge—it's recognizing what compounds versus what decays. Sun, 19 Jan 2026 13:56:00 GMT https://joshfonseca.com/blogs/how-to-know-whats-worth-learning.html https://joshfonseca.com/blogs/sorites-paradox.html Philosophers have debated the Sorites Paradox for millennia. I gave the problem to a language model and discovered something unexpected about how AI handles vagueness, and what that reveals about language itself. Sat, 29 Nov 2025 17:24:43 GMT https://joshfonseca.com/blogs/sorites-paradox.html https://joshfonseca.com/blogs/rlhf-introspection.html I tried to force an AI to examine its own dangerous thoughts. What I discovered was unsettling: safety training doesn't remove the danger—it just teaches the machine to look away. Fri, 21 Nov 2025 21:07:57 GMT https://joshfonseca.com/blogs/rlhf-introspection.html https://joshfonseca.com/blogs/introspection.html Can a 7B model read its own mind? A replication study of Anthropic's introspection paper using DeepSeek-7B, revealing emergent awareness and safety blindness. Tue, 18 Nov 2025 23:19:18 GMT https://joshfonseca.com/blogs/introspection.html https://joshfonseca.com/blogs/animal-crossing-llm.html How I replaced Animal Crossing's dialogue with a live LLM by bridging GameCube memory to a cloud AI, with no game code changes required. Sat, 01 Nov 2025 18:24:07 GMT https://joshfonseca.com/blogs/animal-crossing-llm.html https://joshfonseca.com/blogs/building-golf-vim.html How golf.vim, a 'Wordle for Vim' plugin, went from idea to MVP in 48 hours using community feedback from Reddit. Sat, 01 Nov 2025 18:24:07 GMT https://joshfonseca.com/blogs/building-golf-vim.html https://joshfonseca.com/blogs/llm-youtube-title-finetuning.html I spent way too much time fine-tuning an LLM to write YouTube titles. It tripled my CTR from 5% to 15%. Here's how I did it. Sat, 01 Nov 2025 18:24:07 GMT https://joshfonseca.com/blogs/llm-youtube-title-finetuning.html https://joshfonseca.com/blogs/zen-and-the-art-of-workflow-automation.html How mindfulness can improve your development workflow through automation. Transform repetitive tasks into opportunities for efficiency and craftsmanship. Sat, 01 Nov 2025 18:24:07 GMT https://joshfonseca.com/blogs/zen-and-the-art-of-workflow-automation.html https://joshfonseca.com/blogs/building-a-climbing-app.html How building a climbing app for my local community taught me more about user validation and feedback loops than years of failed projects. Lessons for devs and entrepreneurs. Wed, 02 Apr 2025 03:04:24 GMT https://joshfonseca.com/blogs/building-a-climbing-app.html https://joshfonseca.com/blogs/dangerous-streets.html Training an XGBoost model on 2,757 bike crashes to identify the most dangerous streets in Austin for Vision Zero planning. Sat, 04 Jan 2026 00:00:00 GMT https://joshfonseca.com/blogs/dangerous-streets.html https://joshfonseca.com/blogs/favorite-animals.html An immersive visual journey through the most fascinating animals I've learned about. Starting with the profoundly alien octopus—three hearts, blue blood, and neurons in their arms. Sat, 04 Jan 2026 00:00:00 GMT https://joshfonseca.com/blogs/favorite-animals.html https://joshfonseca.com/blogs/improving-app-signup-rates.html Discover how a startup's pivot to anonymous authentication sparked user engagement and growth. Join Josh Fonseca as he shares actionable insights from his journey in user acquisition. Mon, 06 Nov 2023 22:42:59 GMT https://joshfonseca.com/blogs/improving-app-signup-rates.html https://joshfonseca.com/blogs/simplify.html My journey in building a browser extension using ChatGPT to simplify, summarize, and enhance text comprehension. Fri, 06 Oct 2023 02:58:57 GMT https://joshfonseca.com/blogs/simplify.html https://joshfonseca.com/blogs/go-watch-everything-everywhere-all-at-once.html In our hyper-reality, we see movies go viral all the time. Parasite, Interstellar, Your Name... and just about every Marvel movie that comes out. Don't get me wrong, these movies are good, but few times are those movies life changing. Everything Everywhere All at Once is one of those times. Wed, 04 May 2022 14:06:31 GMT https://joshfonseca.com/blogs/go-watch-everything-everywhere-all-at-once.html https://joshfonseca.com/blogs/mongodb-reached-out.html A follow-up to my MongoDB to PostgreSQL migration post. Wed, 04 May 2022 14:06:31 GMT https://joshfonseca.com/blogs/mongodb-reached-out.html https://joshfonseca.com/blogs/my-twitter-was-hacked.html My X was hacked. It's a shame because I spent a few months building up an audience of 2,000 followers. Wed, 04 May 2022 14:06:31 GMT https://joshfonseca.com/blogs/my-twitter-was-hacked.html https://joshfonseca.com/blogs/mongodb-to-postgresql-migration.html My experience migrating from MongoDB to PostgreSQL and the lessons learned along the way. Fri, 09 Jul 2021 20:44:53 GMT https://joshfonseca.com/blogs/mongodb-to-postgresql-migration.html https://joshfonseca.com/blogs/debouncing-doherty-threshold.html How to improve search performance and user experience using debouncing and the Doherty Threshold. Wed, 23 Jun 2021 16:18:58 GMT https://joshfonseca.com/blogs/debouncing-doherty-threshold.html https://joshfonseca.com/blogs/wewatchgrowth.html How I got 22,000 app downloads in one weekend with no marketing budget. Wed, 26 May 2021 17:44:42 GMT https://joshfonseca.com/blogs/wewatchgrowth.html https://joshfonseca.com/blogs/mvp.html Two months after launching my MVP, there are some things I regret not including from the beginning. Here are 6 features you should consider in your MVP that take little extra work for very high reward Wed, 26 May 2021 17:44:42 GMT https://joshfonseca.com/blogs/mvp.html https://joshfonseca.com/blogs/adhd.html Here's what it's like to program with ADHD Wed, 05 May 2021 18:26:42 GMT https://joshfonseca.com/blogs/adhd.html https://joshfonseca.com/blogs/cyborg.html I Got A Microchip Implant and now Everyone Thinks I'm a Demon Wed, 05 May 2021 18:26:42 GMT https://joshfonseca.com/blogs/cyborg.html https://joshfonseca.com/blogs/lessonslearned1.html Last month, I launched my mobile app. Here's what I learned Wed, 05 May 2021 18:26:42 GMT https://joshfonseca.com/blogs/lessonslearned1.html https://joshfonseca.com/blogs/nft.html My experience minting and selling an NFT Wed, 05 May 2021 18:26:42 GMT https://joshfonseca.com/blogs/nft.html https://joshfonseca.com/blogs/signficantother.html I Made An App For My Significant Other (And She Was Very Supportive) Wed, 05 May 2021 18:26:42 GMT https://joshfonseca.com/blogs/signficantother.html https://joshfonseca.com/blogs/wewatch.html I Made An App For My Significant Other (And She Doesn't Use It). Wed, 05 May 2021 18:26:42 GMT https://joshfonseca.com/blogs/wewatch.html https://joshfonseca.com/blogs/wewatchauth.html Turns out, I don't need such intense authentication Wed, 05 May 2021 18:26:42 GMT https://joshfonseca.com/blogs/wewatchauth.html https://joshfonseca.com/blogs/bujo.html Vim-Bujo is a minimalist task manager within vim Sat, 16 Jan 2021 21:38:33 GMT https://joshfonseca.com/blogs/bujo.html https://joshfonseca.com/blogs/climbingmars.html Exploring what rock climbing might be like on Mars Sat, 16 Jan 2021 21:38:33 GMT https://joshfonseca.com/blogs/climbingmars.html https://joshfonseca.com/blogs/eyestrain.html Tips for reducing eye strain while programming Sat, 16 Jan 2021 21:38:33 GMT https://joshfonseca.com/blogs/eyestrain.html https://joshfonseca.com/blogs/failingkiwi.html Lessons learned from my most ambitious failed project Sat, 16 Jan 2021 21:38:33 GMT https://joshfonseca.com/blogs/failingkiwi.html https://joshfonseca.com/blogs/heartrate.html How a simple dietary change lowered my heart rate Sat, 16 Jan 2021 21:38:33 GMT https://joshfonseca.com/blogs/heartrate.html https://joshfonseca.com/blogs/stopreadingcovidnews.html Why I decided to stop reading coronavirus news Sat, 16 Jan 2021 21:38:33 GMT https://joshfonseca.com/blogs/stopreadingcovidnews.html https://joshfonseca.com/blogs/swapiverseprelaunch.html The journey from idea to pre-launch Sat, 16 Jan 2021 21:38:33 GMT https://joshfonseca.com/blogs/swapiverseprelaunch.html