What Codex unlocks for Notion

2 Weeks → 3 hours

Codex reduced development time

At Notion, Codex is changing how engineers build. The company is rethinking the software primitives and abstractions it builds so that agents can use them. When bringing a new engineer onto the team, they're hiring for curiosity and open-mindedness, since the years of experience the field would normally call for don't exist yet. And managers who hadn't written production code in years are back in the codebase, shipping alongside their teams.

Ryan Nystrom runs AI Product Engineering at Notion. In his year-plus tenure, his team has built or touched nearly every AI feature in the product. They’re finding that turning to Codex has unlocked new possibilities for what they can take on.

“What I appreciate about Codex is that it takes its time to figure things out before actually building. The result is that usually what it builds is to our codebase’s standards off the bat, rather than me having to go back and clean up a bunch of its work.”

Building Notion’s AI voice input on the web

Codex’s ability to autonomously execute showed up clearly in a recent project. Ryan exclusively used Codex to bring Notion’s AI voice input to the web.

"When we talk, we can provide so much more context," he says. "If I'm typing, I'm thinking about my prose, what words I'm using. By giving this feature to users on Notion, they're able to ask more organic questions and include a lot more context. We wanted to bring that to Notion AI."

When the feature request came in, Notion's mobile app already had a functional version, but the desktop and web client didn't. Even though Ryan wasn't entirely sure how the feature worked on mobile, he was able to give the problem to Codex. He pointed it at the mobile codebase, gave it a clear description of how it would need to look on the web, and provided a way to verify the result. Codex came back with a complete first cut of the web implementation, in one shot, that matched Notion's codebase conventions closely enough to ship the next day.

"If I were to build the Notion voice input feature two years ago, this is a project that would've taken me and maybe another engineer two weeks," Ryan says. "With Codex, I was able to build this in maybe three or four hours, entirely by myself."

“It spent a bunch of time exploring our mobile code, and then finally came back and wrote the entire feature basically in one shot. I shipped it the next day and immediately started letting users test it.”

How the work has changed

Engineers at Notion can routinely hand Codex a set of tasks and a way to check its work, then step away while it runs. "I've almost found myself spending a lot more time writing these spec documents that I can hand to Codex and let it work on," Ryan says. "Honestly, I don't really write code by hand anymore."

Before Codex, each engineer on the team could really focus on only one task at a time, squeezed between meetings and supporting peers. Now they're running multiple tasks in parallel, firing off work without losing any of the team support that used to be the bottleneck.

"I manage a team of people, and traditionally managers haven't had time to write code," he says. "The fact that I can build a feature solo while still supporting my team is crazy. I've been managing for five-plus years and never been able to go this deep on coding problems."

Now he can simply queue up a task, head into a block of meetings, and come back to a finished feature. Or he and his team get a manager who can ship alongside them, and Ryan gets back a part of the job he'd assumed he had traded away. This availability runs past the workday, too. He'll pose a research question before bed, let Codex run overnight, and wake up to a finished report.

Codex has reset the baseline for what a small team (even a team of one!) can ship, and given Notion's engineers more room to focus on the work they care about most.

“Whenever I need to research a task, fix a bug, or make a little tweak, Codex is just there, ready and willing. Basically, I’ve got an intern available at Notion 24/7.”