# mustafafurniturewala.com

> Personal website and blog of Mustafa Furniturewala, Chief Technology Officer at Coursera.

## About
Mustafa Furniturewala is the CTO at Coursera and joined the company in 2014. This site has interactive courses on AI and engineering, side projects, press, talks, travel itineraries, and some writing.

## Courses
- [The Mechanism — What a Transformer Actually Computes](https://mustafafurniturewala.com/courses/transformer-mechanism-course): Part 1 of a five-part series on how LLMs work. The forward pass step by step: attention, the residual stream, and where the parameters live.
- [The Training Stack — What It Costs to Make a Model](https://mustafafurniturewala.com/courses/training-stack-course): Part 2. Scaling laws worked out as unit economics: training compute, memory per parameter, parallelism, and why Chinchilla's headline fit didn't replicate.
- [Post-Training — How a Document Completer Becomes an Assistant](https://mustafafurniturewala.com/courses/post-training-course): Part 3. SFT, RLHF and DPO, with DPO's closed form derived step by step, and what that shortcut costs.
- [Evals — Error Analysis First, and Judges You Have Validated](https://mustafafurniturewala.com/courses/llm-evals-error-analysis-course): Part 4. Read traces and label the failures before picking a metric, then check an LLM judge like any other classifier before trusting its pass rate.
- [Inference Economics — Why Decode Is Bandwidth-Bound and What It Costs](https://mustafafurniturewala.com/courses/inference-economics-course): Part 5. Why decoding is limited by memory bandwidth, why the KV cache caps how many users a server can hold, and what that does to serving costs.
- [The New Rules of Context Engineering for Claude 5 Models](https://mustafafurniturewala.com/courses/context-engineering-claude5-course): Based on Thariq's July 2026 article on how prompting changes for Claude 5 models, with applied modules on CLAUDE.md, skills and tool design.
- [The Context Budget — Tokens, Skills and Memory as an Enterprise Decision](https://mustafafurniturewala.com/courses/enterprise-context-economics-course): Skills, CLAUDE.md, memory, retrieval, MCP and subagents compared as different ways to decide what the model sees, and what each one costs per turn.
- [Claude Mods — Reading a Feature Before It Ships](https://mustafafurniturewala.com/courses/claude-mods-function-hooks-course): How Claude Code's extension model is moving from hooks that vote on an action to mods that wrap it, read from a public issue and published source before release.
- [What to Do About Slop — The Cherny Exchange, Examined](https://mustafafurniturewala.com/courses/ai-slop-cherny-exchange-course): A close reading of the email exchange Boris Cherny published about AI-written code in an old codebase, and what each side actually argued.
- [The Attention Factory — Reading OpenAI's Agentic Pipeline](https://mustafafurniturewala.com/courses/openai-software-factory-course): OpenAI's nine-stage agent pipeline, read as a system for deciding what a person should look at rather than a system for writing code.
- [The AI-Native SDLC, Audited](https://mustafafurniturewala.com/courses/ai-native-sdlc-course): Anthropic's playbook for running each stage of software delivery with agents, checked against METR, DORA 2025 and other published evidence.
- [Price and Pace — Measuring AI Progress from the Outside and the Inside](https://mustafafurniturewala.com/courses/measuring-ai-progress-course): Epoch AI's estimate of how fast the cost of AI is falling, next to Anthropic's proposal for measuring progress from inside a lab.
- [We Must Pace the Frontier — Amodei's Argument, Examined](https://mustafafurniturewala.com/courses/pacing-the-frontier-course): Dario Amodei's September 2026 essay laid out as a chain of claims, then tested against its sources and the main objections.
- [Jev — AI That Doesn't Talk](https://mustafafurniturewala.com/courses/jev-system-one-course): TypeSafe AI's Jev returns typed answers with probabilities instead of chat. What its calibration does and doesn't guarantee, and the economic bet behind it.
- [Suncatcher — The Engineering Case for AI Compute in Orbit](https://mustafafurniturewala.com/courses/suncatcher-orbital-compute-course): The engineering in Google's paper on putting TPUs in orbit: power, laser links between satellites, and radiation, with measured results kept apart from projections.

## Writing
- [My Vibe Coding Workflow: How I Ship Side Projects Fast](https://mustafafurniturewala.com/writing/vibe-coding-workflow/): How I build side projects with AI coding tools: the setup, the loop, and what to watch out for.
- [Tech Stack Recommendations for Modern Development](https://mustafafurniturewala.com/writing/tech-stack-recommendations/): What I'd reach for when picking a tech stack in mid-2025: full-stack web, enterprise, mobile, and ML, plus design system choices.

## Travel Itineraries
- [Toronto: A Work Week with a Birthday Weekend Front-Loaded Onto It](https://mustafafurniturewala.com/travel/toronto/): A work trip to Toronto with the family flown in for the first weekend — my daughter's birthday, spent on the Toronto Islands. The format that makes a work trip worth bringing everyone along for.
- [Alaska with Kids: A Girdwood Base & Day Trips to the Glaciers](https://mustafafurniturewala.com/travel/alaska/): A multigenerational family trip to Southcentral Alaska — the trip that replaced a postponed Iceland. One base in Girdwood, day trips out to a glacier cruise in Whittier, wildlife in Portage, and Flattop above Anchorage. Shorter than planned, and better for it.
- [Istanbul & Ankara: A Work Trip to Turkey](https://mustafafurniturewala.com/travel/turkey/): Mostly meetings and kebabs — a work trip to Istanbul and Ankara with some food highlights and notes for anyone with more free time than I had.
- [Dublin: 10 Days Between Work and Wandering](https://mustafafurniturewala.com/travel/dublin/): A solo work trip to Dublin that turned into something more — Georgian streets, Kilmainham, Phoenix Park, and enough pubs to have opinions.
- [Paris & Amsterdam: Spring Break with Family](https://mustafafurniturewala.com/travel/paris-amsterdam/): 10 days in Paris and Amsterdam with 4 adults and 3 kids — Montmartre mornings, the Louvre, Notre-Dame, Keukenhof in bloom, and canal walks through Jordaan.
- [Tokyo, Kyoto & Hakone: 14 Days of Cherry Blossoms & Culture](https://mustafafurniturewala.com/travel/tokyo-kyoto-hakone/): 14 days in spring: Tokyo neighborhoods, Kyoto temples, and hot springs in Hakone.
- [Kyushu Road Trip: 14 Days Exploring Japan's Southern Island](https://mustafafurniturewala.com/travel/kyushu-japan/): A 14-day road trip through Kyushu's volcanoes, cities, and onsen towns, ending with two days in Tokyo.
- [Costa Rica: 10 Days of Volcanoes, Rainforests & Beaches](https://mustafafurniturewala.com/travel/costa-rica/): 10 days in Costa Rica: hot springs at Arenal, the blue water at Rio Celeste, the Monteverde cloud forest, and Pacific beaches.
- [Switzerland: 10 Days of Alps, Lakes & Scenic Trains](https://mustafafurniturewala.com/travel/switzerland/): 10 days in the Swiss Alps in summer: Lucerne, Wengen, the Golden Pass train, and Montreux.
- [Vegas & Zion: 6 Days of Desert Adventure](https://mustafafurniturewala.com/travel/vegas-zion/): Six days over spring break: Las Vegas, then Zion National Park, with kids.

## Projects
- [Driving Simulator](https://car-simulator-xi.vercel.app): A 3D driving game with engine audio synthesized live in the browser rather than sampled. Free roam, races against AI, drift scoring, and collision damage that deforms the car mesh.
- [Family Game Night](https://taboo-game-seven.vercel.app): A mobile-friendly game hub with 8 party games: Taboo, Trivia, Charades, Pictionary, Would You Rather, Word Association, Family Feud, and Codenames. Built as a single HTML file with no dependencies.
- [Gearbox Island](https://gearbox-island.vercel.app): A 3D learning game on an island across the water from Toybox City. You drive to four subject buildings (math, reading, science and geography) for a daily quest, and correct answers earn gears to spend on paint jobs, a go-kart and things for the island. Claude writes each day's questions, with a built-in question bank as the fallback.
- [Markdown Viewer](https://markdown-viewer-navy.vercel.app): A split-pane Markdown editor: CodeMirror with optional Vim keys on one side, a live GitHub-flavored preview with a table of contents on the other. Files save in the browser and export to HTML or PDF, and the same code packages as an Electron desktop app.
- [Open Flight Sim](https://flight-simulator-vert.vercel.app): A browser flight simulator with real aerodynamics — lift, drag, and atmospheric density modeled per frame across a Cessna 172 and a Citation CJ1. Streams real-world terrain, with night flying, weather, and multiplayer.
- [PyQuest](https://python-programming-tutotirla.vercel.app): An interactive Python course that runs a real Python interpreter in the browser via WebAssembly — no server, no setup. Learners write and run code inline, with an AI tutor for hints.
- [SleepTrack Pro](https://apps.apple.com/us/app/sleeptrack-pro/id6757655605): A sleep tracking app that uses on-device sensors to track sleep stages, detect snoring, and record motion. Everything is processed on the device.
- [Read Later](https://www.read-later.org/): A simple read-it-later app, inspired by Pocket. Save articles, organize them, and read them later without distractions.
- [Toybox City](https://toybox-city.vercel.app): An open-world island rendered as a toy diorama, where you hop between ten vehicles — bike, fire truck, helicopter, boat, plane — across 14 missions. The town runs on its own: villagers commute between houses, and three of them hold real AI conversations, falling back to scripted lines offline.
- [Slidora](https://slidora.ai/): An AI tool that turns ideas into slide decks, with suggestions for content and design.

## Other Pages
- [Talks](https://mustafafurniturewala.com/talks): Recordings of panels and interviews, plus one slide deck
- [Press](https://mustafafurniturewala.com/press): Interviews and news coverage
- [RSS Feed](https://mustafafurniturewala.com/rss.xml): New writing and travel posts
- [JSON Feed](https://mustafafurniturewala.com/feed.json): The same feed as JSON