How does ChatGPT work? As explained by the ChatGPT team. - The Pragmatic Engineer
Sometimes the best explanations of how a technology solution works come from the software engineers who built it. To explain how ChatGPT (and other large language models) operate, I turned to the ChatGPT engineering team. I asked this from Evan Morikawa at OpenAI. Evan joined OpenAI in 2020 – two years before ChatGPT launched – and has led the Applied engineering team as ChatGPT launched and scaled. His team was the one that created ChatGPT, and Evan has been there from the very beginning. With this, it’s over to Evan. My questions are in italic. Evan: how did you join OpenAI, and end up heading the Applied engineering group – which also builds ChatGPT? OpenAI is the creator of ChatGPT, which is just one of the business’ products. Other shipped things include DALL·E 3 (image generation,) GPT-4 (an advanced model,) and the OpenAI API which developers and companies use to integrate AI into their processes. ChatGPT and the API each expose several classes of model: GPT-3, GPT-3.5, and GPT-
Before we start: I'm hosting the first-ever The Pragmatic Summit on 11 February, 2026, in San Francisco. Join 400 top engineers and leaders as we answer the question: How is AI reshaping software engineering, dev workflows, and the modern engineering stack? Spaces are limited - don't miss out! Buy tickets here . --> See a longer version of this article here: Scaling ChatGPT: Five Real-World Engineering Challenges. Sometimes the best explanations of how a technology solution works come from the software engineers who built it. To explain how ChatGPT (and other large language models) operate, I
related reading
- What Is ChatGPT Doing … and Why Does It Work?-Stephen Wolfram Writingswritings.stephenwolfram.com
- Inside OpenAI: How does ChatGPT Ship So Quickly?newsletter.pragmaticengineer.com
- GPT-4openai.com
- Deep Dive into LLMs like ChatGPTyoutube.com
- Generative AI: A New Generation of AI - by Josh Houjoshhou.substack.com
- GitHub - brexhq/prompt-engineering: Tips and tricks for working with Large Language Models like OpenAI's GPT-4.github.com
- What Is ChatGPT Doing … and Why Does It Work?-Stephen Wolfram Writingswritings.stephenwolfram.com
- How LLMs Work, Explained Without Math - miguelgrinberg.comblog.miguelgrinberg.com
- Let's build GPT: from scratch, in code, spelled out.youtube.com
- Why didn't DeepMind build GPT3?rootnodes.substack.com
- Prompt engineering | OpenAI APIplatform.openai.com
- ChatGPT Free vs. Paid - What's the difference?youreverydayai.com