An Engineer's Diary Reveals the Human Cost of Building OpenAI's Next Big Thing

Behind the seemingly magical abilities of OpenAI’s technology lies a story of intense human effort and immense personal sacrifice. In a candid reflection posted on July 15, former top engineer Calvin French-Owen peeled back the curtain on the company’s high stakes culture. He detailed a product launch that was “unquestionably one of the highlights of my career” but also the “hardest I’ve worked in nearly a decade.”

French-Owen is a seasoned tech leader who cofounded the successful data company Segment, according to his profile on LinkedIn. He was not a wide eyed junior developer; he was a veteran who understood the demands of the industry. Yet even he was struck by the intensity of the sprint to build and launch Codex, an ambitious AI agent designed to write and edit software, after joining OpenAI in May 2024.

The project went from the first line of code to a full public launch in a breathtaking seven weeks.

“The Codex sprint was probably the hardest I’ve worked in nearly a decade,” French-Owen wrote. He described a relentless schedule that blurred the lines between work and life, all while navigating the challenges of a growing family. “Most nights were up until 11 or midnight. Waking up to a newborn at 5:30 every morning. Heading to the office again at 7a. Working most weekends. We all pushed hard as a team, because every week counted.”

The Final Push

The immense pressure culminated on the night before the scheduled launch. French-Owen and four of his colleagues found themselves in the office in the dead of night, battling a complex and stressful technical challenge. They were trying to deploy the main “monolith,” a term for a large, single piece of software that encompasses an entire application.

Deploying a monolith is like trying to renovate an entire skyscraper at once. Instead of fixing one apartment at a time, you change the plumbing, electrical, and structure of the whole building simultaneously. If a single part fails, the entire system can break, making the operation incredibly high stakes and nerve wracking.

“Five of us stayed up until 4a trying to deploy the main monolith (a multi-hour affair),” he recalled. Just a few hours later, they were back in the office for the 8 AM public announcement and livestream, ready to turn on the features and watch the traffic pour in.

Was the Sacrifice Worth It?

This grueling work ethic exists within the hypercompetitive landscape of artificial intelligence, where OpenAI is in a constant race with giants like Google and Anthropic. The pressure to innovate and launch products quickly is immense. In this case, the result of the team’s sprint was nothing short of staggering.

Since its launch just 53 days ago (May 16), Codex has generated over 630,000 public pull requests. A pull request is the standard way a software engineer submits a finished unit of coding work. This number represents an almost unimaginable level of automated productivity, validating the team’s belief in the product and, in a way, justifying their incredible sacrifice.

French-Owen, who has since left OpenAI for a fresh start, harbors no resentment. He calls the experience the “ride of a lifetime” and “one of the best moves I’ve ever made.” His story, however, offers a sobering and essential look at the human engine powering the AI revolution. It reveals that behind every seamless AI response is a team of brilliant people who have likely pushed themselves to the absolute limit.