Lenny's Podcast: Product | Career | Growth
00:00:00 · Lenny Rachitsky, Fiona Fung
[00:00:00] S0: Anthropic engineers on average have eight times as much code per quarter as they did compared to 2025. [00:00:05] S1: Coding is no longer the bottleneck. It's looked at the ceiling of what anyone is able to do. [00:00:10] S0: Everything is now possible, in theory. Now it's about how ambitious can you be. [00:00:14] S1: It's always something we ask ourselves, what's better than me doing it? Having Claude do it. [00:00:18] S0: The people that seem to be doing best are taking the most initiative, getting the most proactive, have the most agency. [00:00:22] S1: We say with high agency is also high accountability. So it's all about making sure folks have that freedom to cook. But then it's also like, okay, what's the accountability for it? What's the hypothesis of what you're trying to solve? [00:00:33] S0: I'm curious what is lost in this new world of software engineering. [00:00:36] S1: It could start being a lonely experience because we all started just working with our agents so much. And on the Claude Code team recently we started a para-wise programming lunch. [00:00:44] S0: Something you think about is this gap forming between people that are leaning into AI, killing it, and then people that are not, super frustrated, fighting, resisting. [00:00:52] S1: In terms of frustration, I think sometimes I also see a little bit of fear. For anything that there is a fear, my advice is lean in and ask, " What can I do about it? What is within my control?"
00:00:52 · Fiona Fung, Lenny Rachitsky
[00:00:52] S1: In terms of frustration, I think sometimes I also see a little bit of fear. For anything that there is a fear, my advice is lean in and ask, " What can I do about it? What is within my control?" [00:01:05] S0: Today, my guest is Fiona Fung. Fiona leads the teams behind Claude Code and Cowork at Anthropic. She oversees both Boris Cherny and Kat Wu, both of whom who have been on the podcast and whose episodes are in the top 10 most listened to episodes of all time. Before Anthropic at Microsoft, Fiona ran the teams that built TypeScript and Visual Studio. After that, she went to Facebook where she started the Facebook Marketplace team, which she took from idea to launch. Today, Facebook Marketplace generates over $100 billion in GMV every year. Also, while at Meta, she oversaw work on Meta's first smart glasses product and then she helped build Orion, their first AR glasses product. Then she went to Instagram where she led infrastructure, growth, integrity, and safety teams. While at Instagram and at Meta, she oversaw an org of over 500 people. Fiona has been an engineer for over 25 years and as a longtime engineering leader, especially now at Anthropic, she has such a unique lens into where things are heading, what's worth paying attention to, and what teams should be thinking about right now as AI transforms the world of building. [00:02:40] S1: Thanks so much for having me, Lenny.
00:02:40 · Fiona Fung, Lenny Rachitsky
[00:02:40] S1: Thanks so much for having me, Lenny. [00:02:42] S0: So I was at the Code With Claude event, I don't know, a month ago at this point and I went to your talk and I was just like, "Holy shit, I got to get Fiona on this podcast. She's thinking so far ahead of where everybody else is going and where people are at with AI." So you've been an engineer for 25 years. I was browsing your LinkedIn. You started at IBM of all places, such a different place to be these days. [00:03:05] S1: Yes. [00:03:06] S0: And it's just insane how much the job of an engineer has changed over the past just two years. It's like a completely different job. People may forget 100% of code was written by humans not long ago, and now it's getting to 100% of code written by AI. As Boris famously said, coding is solved. Along these lines, there's just this tweet that you guys put out yesterday where you showed, here's the tweet, "Anthropic engineers on average have eight times as much code per quarter as they did compared to '21 to 2025." We'll show this chart on the screen. It's just like stable, stable, stable, stable, shooting off into the moon. So it's just insane how much this role has changed. I'm curious about your kind of path as an engineer living through this, having been an engineer for a long time, what have been kind of like the big moments along the way where it's shifted your way of thinking and operating that have led you to what you do now and how you operate now?
00:04:04 · Fiona Fung
[00:04:04] S1: Oh, I love this kind of love walk back in time. Yeah. IBM, working on DB2, the operating system services team. Back then I was thinking, "Oh, what's a hard area of the stack?" And I really thought the lower level you go closer to the OS, then it's more hardcore and you'll learn more. So I was really fortunate to gone into the IBM internship. But the funny thing was, I think there's even a big shift from IBM to Microsoft. So at IBM it was I think VIM. I didn't have an IDE that we used. I think there might have been an Eclipse license, but for some reasons, most of us didn't use it. So I remembered it was mainly like VIM and kind of terminal debugging. And then when I joined Microsoft, I mean, this is how naive I was, I didn't even know about IDEs and such. And back then you didn't really get to pick teams. His was early 2000s. Actually, first off, I should say I was so grateful that I landed the internship and the role, because to take us all the way back in time, the dot com bubble burst in 2000. And so for my graduating class, a lot of the companies weren't hiring or were hiring freezes. So I was so fortunate when Microsoft extended me an offer. And so they're like, "You're going to work on Visual Studio." I did not even know what Visual Studio was because I came from a Unix school. So I remembered asking, because I was thinking, well, the name Visual Studio, I'm like, "Oh, is this a better Paint program?" And I could tell the look of my manager's face like, "What is going on?" But then it ended up becoming the love of my life for the first 11 years of my career. But that was the first time I used an IDE. So joining the Visual Studio team seeing, "Oh wow, here's an IDE with debuggers and you can set break points and do multi-threaded debugging." That was also always mind-blowing for me to think about the stepwise change. So yeah, that was kind of the story going from IBM to Visual Studio. And then what I really loved actually about Visual Studio is I was on the Visual Studio editor team. So I used a VS editor to build the VS editor and that's where my whole love of dog fitting comes from. I remembered I wanted to first and foremost create a delightful experience, not only for myself, but for my teammates, because also if we go back in that time, if you remember, I mean, when did Twitter come out? Was it 2006 or so?
00:06:22 · Lenny Rachitsky, Fiona Fung
[00:06:22] S0: It feels like it's been around my whole life. [00:06:25] S1: But back then, before social media, it was also harder for most engineers to hear fast customer feedback. For sure, there you would be user research sessions or we would have customers visit us. But you didn't get the rapid feedback that you do nowadays. But back then I was so lucky because I was on VS. We ourselves gave each other so much rapid feedback because we were all heavy VS users on the team. Yeah. When I worked on Visual Studio, back then we also shipped software on CDs. [00:08:20] S0: I remember that.
00:08:20 · Lenny Rachitsky, Fiona Fung
[00:08:20] S0: I remember that. [00:08:22] S1: And that's why they were really hard deadlines because you had to make sure the software was ready for us to give to manufacturing, to then put on the CDs for us to then put on the shelves. And then so once that was another shift when we actually started to be able to ship software online. And I think that's the interesting thing, and I kind of mentioned this in my talk, it's engineering time was really precious resource, but you also have these really hard deadlines, for example, like printing software and CDs. And so back then you would do a lot more planning because you just wanted to make sure given the time you have, you make the best of it. And that's a shift that we're seeing with Claude Code and Cowork is coding is no longer the bottleneck. And so now you showed the tweet and that graphic, but now it's all about where has that shift happened. Now not only engineers, we also have designers, PMs, everybody on the Claude Code team checks in code. So when not only more people checking in code, but kind of different disciplines, but also the throughput is so high, how do we think about verification? That's kind of this other shift that I'm seeing.