whosaid — who said what, by pipeline read-only

0:00David Heinemeier HanssonThere are decades where nothing happens and weeks where decades happen. And we have seen decades of progress happen in the last nine months. If you're not recognizing the gravity of the moment, that's the delusion, that's the psychosis. Who would not get delirious if suddenly a genie pops out of the bottle and says, "You

0:24David Heinemeier Hanssoncan have whatever you want. Every feature you've ever dreamed of in an operating system, I can deliver them to you, most of them in five minutes, a few in 20, and if we really go hog wild, it's gonna take me two hours"? I want the fastest car braking to speed limits. I want the diver watch that can go down the Mariana Trench.

0:44David Heinemeier HanssonI want the operating system that can install in less than 60 seconds. One of the things I always loved about race cars was when I would stumble out of the car absolutely smashed and barely able to hold my head up, and I'd lay down on the garage floor and just think, "Holy fuck, I'm alive." The overtone window does not open

1:03David Heinemeier Hanssonitself. It opens one nudge at a time by people risking a little.

1:09Lex FridmanYeah.

1:09David Heinemeier HanssonA little reputation, a little pushback, a little criticism, or maybe sometimes a lot of reputation or a lot of criticism or a lot of pushback. Creating life with another human that you love is literally the peak experience of being on the planet.

1:28Lex FridmanThe following is a conversation with David Heinemeier Hansson, also known as DHH, creator of Ruby on Rails, CTO of 37signals, creator of the new Amachi Linux operating system, best-selling author, race car driver, and one of the most outspoken and prolific programmers in the world. For the past 20-plus years, for him, programming

1:52Lex Fridmanmeant meticulously handcrafting beautiful Ruby code. But recently, since late 2025, DHH has embraced the AI revolution and has openly transformed himself into, once again, one of the most outspoken and prolific agentic engineers, even though he hates that term. So let's say practitioners of whatever programming is becoming

2:18Lex Fridmanwhere AI is doing most of the actual programming and the human steers the ship with high-level design, vision, and taste. Yes, it's true, DHH is at times controversial, but he's always fearless, brilliant, and fun to talk to. This was, once again, an intense, eye-opening, and a wild rollercoaster ride of a conversation.

2:41Lex FridmanThis is a Lex Fridman podcast. To support it, please check out our sponsors in the description where you can also find links to contact me, ask questions, give feedback, and so on. And now, dear friends, here's DHH.

2:56Lex Fridman13 months ago, we sat down right here to talk about programming, and then, uh, everything changed. At that time, you were a bit skeptical about the role of AI in the process of programming, and then we went through this rapid evolution of, uh, a- agentic engineering. So, uh, simple question to start: How has your view on

3:19Lex FridmanAI's role in programming changed? Are you excited? Are you terrified? Are you on an emotional rollercoaster ride?

3:26David Heinemeier HanssonI am incredibly excited.

3:29Lex FridmanYou've been talking about fun a lot.

3:31David Heinemeier HanssonThere is none of the existential threat. That doesn't exist for me as an emotional component. It is only there as an intellectual component, and the emotional component for me is 100% pure, unadulterated joy-

3:47Lex FridmanHmm

3:47David Heinemeier Hansson... and optimism and amazement that we've made computers do this. And I find it so interesting that we talked just 13 months ago because

3:59David Heinemeier Hanssonit's like we talked in different universes, different eras.

4:02Lex FridmanHmm.

4:03David Heinemeier HanssonI love this quote, I think it's Lenin: "There are decades where nothing happens and weeks where decades happen." And we have seen decades of progress happen in the last nine months. I mean, imagine you're there when the Wright brothers take flight.

4:21Lex FridmanYeah.

4:21David Heinemeier HanssonYesterday, The New York Times would write, "It's gonna be 10,000 years before we fly," and then the day after, we're up in the skies, and just a few years after that, there were cross-Atlantic planes. The whole world has completely changed. What a blessing to be there in that moment. If you zoom out and look at all of human

4:40David Heinemeier Hanssonhistory, how many humans got to live within the same epoch that they were born in? They never saw that complete change of the world and of society. And to have been blessed with two of those

4:58David Heinemeier Hanssonfeels just such a privilege. I got to see the internet-

5:01Lex FridmanMm-hmm

5:02David Heinemeier Hansson... from pre-internet to post-internet, and then now pre-AI, post-AI. What an amazing run. How fortunate.

5:12Lex FridmanYeah, but the thing is, this feels like a thing that happened faster than anything else in human history.

5:18David Heinemeier HanssonCorrect.

5:18Lex FridmanSo I, I would say somewhere around December, maybe late November-

5:22David Heinemeier HanssonNovember 24.

5:24Lex FridmanThis is...

5:26David Heinemeier HanssonThat's the exact moment.

5:26Lex FridmanYou know, when they talk about when one nation invades another in a world war or something like this, it, this is how we talk about AI changing everything. Yeah, the... and it really just sh- shifted from many great developers. It shifted to where AI is doing some, uh, basic auto-complete, maybe writing 5, 10, 15, 20% of

5:47Lex Fridmancode to writing 80% of code.

5:49David Heinemeier HanssonOr 100.

5:50Lex FridmanOr 100, yeah, especially if it's not a, a public-facing product.

5:54David Heinemeier HanssonTo me, that's why even when I look back upon our conversation a year ago, I don't actually have different opinions. I have the same opinions. A year ago, I did not like the mode of AI we were offered. It was the autocomplete mode, or it was the AI chatbot mode. Now, the chatbot I actually liked, as we talked about. Great

6:16David Heinemeier Hanssontutor right from the get-go, great way of looking things up on the internet. Not what was gonna replace me chiseling code. But- ... then we get the agents.

6:28Lex FridmanYeah.

6:28David Heinemeier HanssonAnd the agents start out being curiosities for about five minutes, and then they get amazing, and then they get, "Oh my God, is this AGI?"

6:41Lex FridmanYeah.

6:41David Heinemeier HanssonAnd all of that happened since last year, even just in, within the last nine months. We have basically these few phases here. We have AI in the pre-agentic era. I was excited about that, but it was not fundamentally rewriting the rules of the game for me. It was not completely changing how I worked. I was still chiseling

7:04David Heinemeier Hanssoncode, I just had a little helper, a little sidekick-

7:08Lex FridmanMm-hmm

7:08David Heinemeier Hansson... who could bounce ideas off, and I could look up this, uh, information online and so forth in a more efficient way. It was just a more efficient way to do what I was already doing, and it didn't change the emotional connection I had to, to the computer. Then we get to November 24th, 2025. Opus 4.5, to me, was the dividing

7:31David Heinemeier Hanssonline, where suddenly... I didn't even try it on the 24th. I think I tried it on the 26th.

7:38David Heinemeier HanssonI give it a couple of tasks, and I realize that the quality of the output is uncannily close to what I would've written. And I, I remember just leaning back and thinking, "What just happened?"

7:55Lex FridmanMm-hmm.

7:55David Heinemeier Hansson"How, how did we go from this autocomplete mess that I was talking to you about in the summer to this just a few short months later? How did we get both the increase in intelligence and then also the increase in usability?" This agent harness question, where

8:15David Heinemeier HanssonI don't know if Opus 4.5 was that much smarter than Opus 4, which is what we had in the summer, but its ability to instrument your computer, to use tools, to check its own work, to apply its intelligence in such a way that you could get real meaningful work out of it, was completely different. And I think this is then the

8:38David Heinemeier Hanssonbig change that happens for almost anyone who paid attention and started playing with it over the Christmas break. This is what I heard-

8:44Lex FridmanYeah

8:44David Heinemeier Hansson... from Shopify and other places with lots of employees, who

8:49David Heinemeier Hanssonsuddenly had a breather, suddenly had a couple of weeks to lean back and just look at what was going on, gave it a try, and had the same mind-blowing experience that these agents were of a different genre than what we had before. And then what we get to is

9:08David Heinemeier HanssonI'm already excited at this point. Like, by December, I'm already revisiting sort of all my priors-

9:15Lex FridmanMm-hmm

9:15David Heinemeier Hansson... and going like, "Wow, if it can do this, can it also do that?"

9:18Lex FridmanMm-hmm.

9:18David Heinemeier Hansson"Oh, yeah, it can." And again, Opus 4.5 now looks like a retarded model.

9:26Lex FridmanYeah.

9:26David Heinemeier HanssonAnd this is the

9:28David Heinemeier Hanssonmagic of this progress, is you think you've reached something... I remember thinking at the moment, "If this is the last model we get, I'll be set."

9:38Lex FridmanYeah.

9:38David Heinemeier Hansson"I'll be happy."

9:39Lex FridmanYep.

9:39David Heinemeier Hansson"I could live with Opus 4.5 for the next 20 years-"

9:42Lex FridmanYep

9:42David Heinemeier Hansson... and you would hear no complaints from me." Because it was just so incredibly amazing to see an agent do all this work in the way that I wanted it done. Because it was not just about it being able to solve a task, it was also that I could look at its path-

0:00There are decades where nothing happens and weeks where decades happen.

0:05And we have seen decades of progress happen in the last nine months.

0:11If you're not recognizing the gravity of the moment, that's the delusion.

0:18That's the psychosis.

0:19Who would not get delirious if suddenly a genie pops out of the bottle and says,

0:24you can have whatever you want.

0:25Every feature you've ever dreamed of in an operating system, I can deliver them to you.

0:32Most of them in five minutes, a few in 20.

0:34And if we really go hog wild, it's going to take me two hours.

0:38I want the fastest car breaking the speed limits.

0:40I want the diver watch that can go down the Mariana Trench.

0:44I want the operating system that can install in less than 60 seconds.

0:48One of the things I always loved about race cars was when I would stumble out of the car,

0:53absolutely smashed and barely able to hold my head up. And I lay down on the garage floor and

0:58just think, holy fuck, I'm alive. The overtone window does not open itself. It opens one nudge

1:05at a time by people risking a little. A little reputation, a little pushback, a little criticism,

1:12or maybe sometimes a lot of reputation or a lot of criticism or a lot of pushback.

1:16Creating life with another human that you love is literally the peak experience of being on the planet.

1:27The following is a conversation with David Heinemeyer Hansen, also known as DHH.

1:33creator of Ruby on Rails, CTO of 37signals, creator of the new Amachi Linux operating system,

1:41best-selling author, race car driver, and one of the most outspoken and prolific programmers

1:47in the world. For the past 20 plus years, for him, programming meant meticulously hand-crafting

1:54beautiful Ruby code. But recently, since late 2025, GHH has embraced the AI revolution and has

2:03openly transformed himself into, once again, one of the most outspoken and prolific agentic

2:09engineers, even though he hates that term. So let's say practitioners of whatever programming

2:17is becoming, where AI is doing most of the actual programming, and the human steers the ship with

2:23high design vision and taste Yes it true DHH is at times controversial but he always fearless brilliant and fun to talk to This was once again an intense eye and a wild

2:38rollercoaster ride of a conversation. This is a Lex Friedman podcast. To support it,

2:44please check out our sponsors in the description, where you can also find links to contact me,

2:49ask questions, give feedback, and so on. And now, dear friends, here's DHH.

2:5613 months ago, we sat down right here to talk about programming, and then everything changed.

3:03At that time, you were a bit skeptical about the role of AI in the process of programming,

3:09and then we went through this rapid evolution of agentic engineering. So,

3:15So, simple question to start.

3:18How has your view on AI's role in programming changed?

3:21Are you excited?

3:22Are you terrified?

3:23Are you on an emotional rollercoaster ride?

3:26I am incredibly excited.

3:29You've been talking about fun a lot.

3:31There is none of the existential threat.

3:35That doesn't exist for me as an emotional component.

3:38It is only there as an intellectual component.

3:41And the emotional component for me is 100% pure unadulterated joy and optimism and amazement that we've made computers do this.

3:52And I find it so interesting that we talked just 13 months ago because it's like we talked in different universes, different eras.

4:02I love this quote.

4:03I think it's Lennon.

4:05There are decades where nothing happens and weeks where decades happen.

4:09And we have seen decades of progress happen in the last nine months.

4:17I mean, imagine you're there when the Wright brothers take flight.

4:21Yesterday, the New York Times would write, it's going to be 10,000 years before we fly.

4:25And then the day after, we're up in the skies.

4:29And just a few years after that, they're cross Atlantic planes.

4:33The whole world has completely changed.

4:36What a blessing to be there in that moment.

4:38If you zoom out and look at all the human history, how many humans got to live within

4:44the same epoch that they were born in?

4:47They never saw that complete change of the world and of society.

4:53And to have been blessed with two of those feels just such a privilege I got to see the internet from pre to post

5:05and then now pre-AI, post-AI.

5:08What an amazing run. How fortunate.

5:12Yeah, but the thing is, this feels like a thing that happened faster

5:16than anything else in human history.

5:18So I would say somewhere around December, maybe late November.

5:22November 24.

5:23this is you know when they talk about moment when one nation invades another in a world war

5:30something like this that this is how we talk about ai changing everything yeah and it really just

5:36shifted for many great developers it shifted to where ai is doing some uh basic autocomplete

5:44maybe writing 5 10 15 20 of code to writing 80 of code or 100 or 100 yeah especially if it's not

5:52a public-facing product. To me, that's why even when I look back upon our conversation

6:00a year ago, I don't actually have different opinions. I have the same opinions. A year ago,

6:05I did not like the mode of AI we were offered. It was the autocomplete mode or it was the AI

6:12chatbot mode. Now, the chatbot I actually liked, as we talked about. Great tutor right from the

6:18get-go great way of looking things up on the internet not what was going to replace me chiseling

6:23code but then we get the agents and the agents start out being curiosities for about five minutes

6:34and then they get amazing and then they get oh my god is this hai and all of that happened since

6:43last year, even just within the last nine months. We have basically these few faces here. We have

6:51AI in the pre-Agentic era. I was excited about that, but it was not fundamentally rewriting the

6:59rules of the game for me. It was not completely changing how I worked. I was still chishling code.

7:04I just had a little helper, a little sidekick who could bounce ideas off, and I could look up this

7:12information online and so forth in a more efficient way. It was just a more efficient

7:16way to do what I was already doing. And it didn't change the emotional connection I had

7:20to the computer Then we get to November 24th 2025 Opus 4 to me was the dividing line where suddenly I didn even try it on the 24th I think I tried it on the 26th

7:38I give it a couple of tasks and I realized that the quality of the output is uncannily

7:47close to what I would have written.

7:49I remember just leaning back and thinking, what just happened? How did we go from this autocomplete mess that I was talking to you about in the summer to this just a few short months later?

8:04How did we get both the increase in intelligence and then also the increase in usability?

8:11This agent harness question where I don't know if Opus 4.5 was that much smarter than Opus 4, which is what we had in the summer.

8:20but its ability to instrument your computer, to use tools, to check its own work,

8:27to apply its intelligence in such a way that you could get real meaningful work out of it

8:34was completely different.

8:36And I think this is then the big change that happens for almost anyone who paid attention

8:40and started playing with it over the Christmas break.

8:43This is what I heard from Shopify and other places with lots of employees who

8:47So suddenly had a breather, suddenly had a couple of weeks to lean back and just look at what was going on, gave it a try and had the same mind blowing experience that these agents were of a different genre than what we had before.

9:04And then what we get to is.

9:08I'm already excited at this point by December, I'm already revisiting sort of all my priors and going, wow, if it can do this, can it also?

9:17do that? Oh yeah, it can. And again, Opus 4.5 now looks like a retarded model. And this

9:26is the magic of this progress is you think you've reached something. I remember thinking

9:34at the moment, if this is the last model we get, I'll be set. I'll be happy. I could live

9:40with Opus 4.5 for the next 20 years and you would hear no complaints from me because it

9:44It was just so incredibly amazing to see an agent do all this work in the way that I wanted

9:52it done because it was not just about it being able to solve a task.

9:57It was also that I could look at its path.

0:00David Heinemeier HanssonThere are decades where nothing happens and weeks where decades happen. And we have seen decades of progress happen in the last 9 months. If you're not recognizing the gravity of the moment, that's the delusion. That's the psychosis. Who would not get delirious if suddenly a genie pops out of the bottle and says, you can have whatever you want? Every feature you've ever dreamed of in an operating system, I can deliver them to you. Most of them in 5 minutes, a few in 20, and if we really go hog wild, it's going to take me 2 hours. I want the fastest car breaking the speed limits. I want the diver watch that can go down the Mariana Trench. I want the operating system that can install in less than 60 seconds. One of the things I always loved about race cars was when I would stumble out of the car Absolutely smashed and barely able to hold my head up. And I lay down on the garage floor and just think, holy fuck, I'm alive. The overtone window does not open itself. It opens one nudge at a time by people risking a little, a little reputation, a little pushback, a little criticism, or maybe sometimes a lot of reputation or a lot of criticism or a lot of pushback. Creating life with another human that you love is literally the peak experience of being on the planet.

1:25Lex FridmanThe following is a conversation with David Heinemeier Hansson, also known as DHH, creator of Ruby on Rails, CTO of 37signals, creator of the new Amache Linux operating system, bestselling author, race car driver, and one of the most outspoken and prolific programmers in the world. For the past 20+ years, for him, programming meant meticulously handcrafting beautiful Ruby code. But recently, since late 2025, GHH has embraced the AI revolution and has openly transformed himself into, once again, one of the most outspoken and prolific agentic engineers, even though he hates that term. So let's say Practitioners of whatever programming is becoming, where AI is doing most of the actual programming and the human steers the ship with high-level design, vision, and taste. Yes, it's true. DHH is, at times, controversial, but he's always fearless, brilliant, and fun to talk to. This was, once again, an intense, eye-opening, and a wild rollercoaster ride of a conversation.

2:40David Heinemeier HanssonThank you.

2:41Lex FridmanThis is the Lex Fridman Podcast. To support it, please check out our sponsors in the description where you can also find links to contact me, ask questions, give feedback, and so on. And now, dear friends, here's DHH. 13 months ago, we sat down right here to talk about programming, and then everything changed. At that time, you were a bit skeptical about the role of AI in the process of programming, and then we went through this rapid evolution of agentic engineering. So, simple question to start, how has your view on AI's role in programming changed? Are you excited? Are you terrified? Are you on an emotional rollercoaster ride?

3:25David Heinemeier HanssonI am incredibly excited.

3:28Lex FridmanYou've been talking about fun a lot.

3:31David Heinemeier HanssonThere is none of the existential dread. That doesn't exist for me as an emotional component. It is only there as an intellectual component, and the emotional component for me is 100% pure, unadulterated joy and optimism and amazement that we've made computers do this. And I find it so interesting that we talked just 13 months ago because it's like we talked in different universes, different eras. I love this quote. I think it's Lenin. There are decades where nothing happens and weeks where decades happen. And we have seen decades of progress happen in the last 9 months. I mean, imagine you're there when the Wright brothers take flight.

4:20Lex FridmanYeah.

4:21David Heinemeier HanssonYesterday, the New York Times would write, it's gonna be 10,000 years before we fly. And then the day after, we're up in the skies. And just a few years after that, there are cross-Atlantic planes. The whole world has completely changed. What a blessing to be there in that moment. If you zoom out and look at all of human history, how many humans got to live within the same epoch that they were born in. They never saw that complete change of the world and of society. And to have been blessed with 2 of those feels just such a privilege. I got to see the internet from pre-internet to post-internet, and then now pre-AI, post-AI. What an amazing run. How fortunate.

5:11Lex FridmanYeah, but the thing is, this feels like a thing that happened faster than anything else in human history. So I would say somewhere around December, maybe late November.

5:22David Heinemeier HanssonNovember 24th.

5:23Lex FridmanThis is— when they talk about—

5:26David Heinemeier HanssonThat's the exact moment.

5:27Lex FridmanWhen one nation invades another in a world war or something like this, this is how we talk about AI changing everything. Yeah, and it really just shifted for many great developers. It shifted to where AI is doing some basic autocomplete, maybe writing 5, 10, 15, 20% of code to writing 80% of code.

5:49David Heinemeier HanssonOr 100.

5:50Lex FridmanOr 100, yeah, especially if it's not a public-facing product.

5:54David Heinemeier HanssonTo me, that's why even when I look back upon our conversation, a year ago, I don't actually have different opinions. I have the same opinions. A year ago, I did not like the mode of AI we were offered. It was the autocomplete mode, or it was the AI chatbot mode. Now, the chatbot I actually liked, as we talked about, great tutor right from the get-go, great way of looking things up on the internet. Not what was going to replace me chiseling code. But Then we get the agents.

6:27Lex FridmanYeah.

6:28David Heinemeier HanssonAnd the agents start out being curiosities for about 5 minutes, and then they get amazing, and then they get, oh my God, is this AGI?

6:39Lex FridmanYeah.

6:40David Heinemeier HanssonAnd all of that happened since last year, even just within the last 9 months. We have basically these few phases here. We have AI in the pre-agentic era, I was excited about that, but it was not fundamentally rewriting the rules of the game for me. It was not completely changing how I worked. I was still chiseling code. I just had a little helper, a little sidekick.

7:08Lex FridmanMm-hmm.

7:08David Heinemeier HanssonWho could bounce ideas off, and I could look up this, uh, information online and so forth in a more efficient way. It was just a more efficient way to do what I was already doing, and it didn't change the emotional connection I had to, to the computer. Then we get to November 24th, 2025. Opus 4.5 to me was the dividing line where suddenly I didn't even try it on the 24th. I think I tried it on the 26th. I give it a couple of tasks and I realize that the quality of the output is uncannily close to what I would've written. And I remember just leaning back and thinking, what just happened? How did we go from this autocomplete mess that I was talking to you about in the summer to this just a few short months later? How did we get both the increase in intelligence and then also the increase in usability? This agent harness question where I don't know if Opus 4.5 was that much smarter than Opus 4, which is what we had in the summer, but its ability to instrument your computer, to use tools, to check its own work, to apply its intelligence in such a way that you could get real meaningful work out of it was completely different. And I think this is then the big change that happens for almost anyone who paid attention and started playing with it over the Christmas break. This is what I heard from Shopify and other places.

8:46Lex FridmanYeah.

8:46David Heinemeier Hanssonwith lots of employees who suddenly had a breather, suddenly had a couple of weeks to lean back and just look at what was going on, gave it a try, and had the same mind-blowing experience that these agents were of a different genre than what we had before. And then what we get to is, I'm already excited at this point, like by December. I'm already revisiting sort of all my priors and going like, wow, if it can do this, can it also do that? Oh yeah, it can. And again, Opus 4.5 now looks like a retarded model.

9:26Lex FridmanYeah.

9:26David Heinemeier HanssonAnd this is the magic of this progress is you think you've reached something. I remember thinking at the moment, if this is the last model we get, I'll be set. I'll be happy.

9:39Lex FridmanYep.

9:39David Heinemeier HanssonI could live with Opus 4.5 for the next 20 years and you would hear no complaints from me because it was just so incredibly amazing to see an agent do all this work in the way that I wanted it done. Because it was not just about it being able to solve a task, it was also that I could look at its patterns.

0:00David Heinemeier HanssonThere are

0:01David Heinemeier Hanssondecades where nothing happens and weeks where decades happen.

0:05David Heinemeier HanssonAnd we have seen

0:07David Heinemeier Hanssondecades

0:08David Heinemeier Hanssonof progress happen

0:10David Heinemeier Hanssonin the last nine months. If you're not recognizing

0:13David Heinemeier Hanssonthe

0:14David Heinemeier Hanssongravity of the moment, that's the delusion.

0:18David Heinemeier HanssonThat's the psychosis.

0:19David Heinemeier HanssonWho would not get delirious if suddenly a genie pops out of the bottle and says, you can have whatever you want. Every feature

0:27David Heinemeier Hanssonyou've ever dreamed of in an operating system, I can deliver them to you.

0:32David Heinemeier HanssonMost of them in five minutes, a few in twenty. And if we really go hog wild, it's gonna take me two hours. I want the fastest car breaking the speed limits. I want the diver watch that can go down the Mariana Trench.

0:44David Heinemeier HanssonI want the operating system that can install in less than sixty seconds. One of the things I always loved about race cars was when I would stumble out of the car, absolutely smashed and barely able to hold my head up, and I lay down on the garage floor and just think, holy fuck. I'm alive. The overtone window does not open itself.

1:04David Heinemeier HanssonIt opens one nudge at a time by people

1:08David Heinemeier Hanssonrisking a little. A little reputation,

1:10David Heinemeier Hanssona little pushback, a little criticism,

1:13David Heinemeier Hanssonor maybe sometimes a lot of reputation or a lot of criticism or a lot of pushback. Creating life with another

1:19David Heinemeier Hanssonhuman that you love

1:21David Heinemeier Hanssonis

1:22David Heinemeier Hanssonliterally the peak experience

1:24David Heinemeier Hanssonof being on the planet.

1:27Lex FridmanThe following is a conversation with David Heinemeier Hansen,

1:31Lex Fridmanalso known as DHH,

1:34Lex Fridmancreator of Ruby on Rails, CTO of thirty seven signals, creator of the new Amache Linux operating system, best selling author, race car driver, and one of the most outspoken

1:46Lex Fridmanand prolific programmers

1:48Lex Fridmanin the world. For the past twenty plus years, for him, programming meant meticulously

1:54Lex Fridmanhandcrafting beautiful Ruby code.

1:56Lex FridmanBut recently,

1:57Lex Fridmansince late twenty twenty five, GHH has embraced the AI revolution

2:03Lex Fridmanand has openly transformed himself into once again one of the most outspoken and prolific agentic engineers,

2:10Lex Fridmaneven though he hates that term.

2:13Lex FridmanSo let's say

2:15Lex Fridmanpractitioners of whatever programming is becoming

2:18Lex Fridmanwhere AI is doing most of the actual programming and the human steers the ship with high level design, vision, and taste.

2:26Lex FridmanYes. It's true. DHH is at times controversial,

2:30Lex Fridmanbut he's always fearless, brilliant, and fun to talk to. This was once again an intense,

2:36Lex Fridmaneye opening, and a wild roller coaster ride of a conversation.

2:41Lex FridmanThis is Alex Friedman podcast. To support it, please check out our sponsors in the description

2:46Lex Fridmanwhere you can also find links to contact me, ask questions, get feedback, and so on.

2:52Lex FridmanAnd now, dear friends, here's DHH.

2:56Lex FridmanThirteen months ago, we sat down right here to talk about programming,

3:00Lex Fridmanand then

3:01Lex Fridmaneverything changed. At that time, you were a bit skeptical

3:06Lex Fridmanabout the role of AI in the process of programming,

3:09Lex Fridmanand then we went through this rapid evolution

3:12Lex Fridmanof

3:13Lex Fridmanagentic

3:14Lex Fridmanengineering. So

3:16Lex Fridmansimple question to start. How has your view on AI's role in programming changed?

3:21Lex FridmanAre you excited? Are you terrified? Are you on an emotional roller coaster ride?

3:26Lex FridmanI am incredibly excited.

3:29Lex FridmanYou've been talking about fun a lot. There is

3:32David Heinemeier Hanssonnone of the

3:34David Heinemeier Hanssonexistential dread.

3:35David Heinemeier HanssonThat doesn't exist for me as an emotional component.

3:39David Heinemeier HanssonIt is only there as an intellectual component. And the emotional component for me is 100%

3:44David Heinemeier Hanssonpure unadulter joy

3:47David Heinemeier Hanssonand optimism

3:48David Heinemeier Hanssonand

3:49David Heinemeier Hanssonamazement that we've made computers do this. And I find it so interesting that we talked just thirteen months ago

3:56David Heinemeier Hanssonbecause

3:59David Heinemeier Hanssonit's like we talked in different universes, different eras. I love this quote. I think it's Lenin.

4:05David Heinemeier HanssonThere are

4:06David Heinemeier Hanssondecades where nothing happens and weeks where decades happen.

4:10David Heinemeier HanssonAnd we have seen

4:13David Heinemeier Hanssondecades

4:13David Heinemeier Hanssonof progress happen

4:15David Heinemeier Hanssonin the last nine months.

4:18David Heinemeier HanssonI mean, imagine you're there when the Wright brothers take flight. Yeah. Yesterday,

4:22David Heinemeier Hanssonthe New York Times would write, it's gonna be ten thousand years before we fly. And then the day after,

4:27David Heinemeier Hanssonwe're up in the skies. And just a few years after that, they cross Atlantic planes. The whole world has completely changed. What a blessing to be there in that moment. If you zoom out and look at all the human history, how many humans got to live within the same

4:45David Heinemeier Hanssonepoch that they were born in? They never saw that complete change

4:50David Heinemeier Hanssonof the world and of society.

4:53David Heinemeier HanssonAnd to have

4:55David Heinemeier Hanssonbeen blessed with two of those

4:57David Heinemeier Hanssonfeels just such a privilege. I got to see the Internet Mhmm. From pre Internet to post Internet,

5:05David Heinemeier Hanssonand then now

5:06David Heinemeier Hanssonpre AI, post AI.

5:09David Heinemeier HanssonWhat an amazing run. How fortunate. Yeah. But the thing is this

5:14Lex Fridmanfeels like a thing that happened faster than anything else in human history. So I I would say somewhere around December,

5:21Lex Fridmanmaybe late November. November 24.

5:24David Heinemeier HanssonThis is

5:26Lex Fridmanyou know, when they talk about moment. When one nation invades another in a world war or something like this, it this is how we talk about AI changing everything. Yeah. The and it really just

5:37Lex Fridmanshifted for many great developers.

5:39Lex FridmanThey shifted to where AI is doing some

5:43Lex Fridmanbasic autocomplete,

5:44Lex Fridmanmaybe writing five, ten, 20%

5:47Lex Fridmanof code to writing 80% of code. Or a 100. Or a 100. Yeah. Especially if it's not a a public facing product.

5:54David Heinemeier HanssonTo me,

5:56David Heinemeier Hanssonthat's why

5:57David Heinemeier Hanssoneven when I look back upon our conversation a year ago,

6:01David Heinemeier HanssonI don't actually have different opinions. I have the same opinions. A year ago, I did not like the mode of AI we were offered. It was the autocomplete mode or

6:11David Heinemeier Hanssonit was the AI chatbot mode. Now the chatbot I actually liked as we talked about. Great tutor right from the get go. Great way of looking things up on the Internet.

6:21David Heinemeier HanssonNot what was gonna replace me chiseling code.

6:25David Heinemeier HanssonBut

6:26David Heinemeier Hanssonthen we get the agents. Yeah. And the agents start out being

6:31David Heinemeier Hanssoncuriosities

6:32David Heinemeier Hanssonfor

6:33David Heinemeier Hanssonabout five minutes, and then they get amazing,

6:36David Heinemeier Hanssonand then they get,

6:38David Heinemeier Hanssonoh my god. Is this AGI?

6:40David Heinemeier HanssonYeah. And all of that happened since

6:43David Heinemeier Hanssonlast year,

6:45David Heinemeier Hanssoneven

6:46David Heinemeier Hanssonjust in within the last nine months. We have basically these few phases here. We have AI in the pre agentic era. I was excited about that, but it was not fundamentally

6:58David Heinemeier Hanssonrewriting the rules of the game for me. It was not completely changing how I worked. I was still christening code. I just had a little helper, a little sidekick Mhmm. Who could

7:10David Heinemeier Hanssonbounce ideas off, and I could look up this

7:13David Heinemeier Hanssoninformation online and so forth in a more efficient way. It was just a more efficient way to do what I was already doing, and it didn't change the emotional connection I had to to the computer.

7:22David Heinemeier HanssonThen

7:23David Heinemeier Hanssonwe get to 11/24/2025.

7:27David Heinemeier HanssonOpus 4.5

7:29David Heinemeier Hanssonto me was the dividing line where suddenly

7:32David Heinemeier HanssonI didn't even try it on the twenty fourth. I think I tried it on the twenty sixth.

7:38David Heinemeier HanssonI give it a couple of tasks,

7:40David Heinemeier Hanssonand I realize

7:41David Heinemeier Hanssonthat the quality of the output

7:45David Heinemeier Hanssonis uncannily

7:47David Heinemeier Hanssonclose to what I would have written.

7:49David Heinemeier HanssonAnd I I remember just leaning back and thinking,

7:54David Heinemeier Hanssonwhat just happened? Mhmm. How did we go from this autocomplete mess that I was talking to you about in the summer

8:01David Heinemeier Hanssonto this

8:02David Heinemeier Hanssonjust a few short months later? How did we get both the increase in intelligence and then also the increase in

8:10David Heinemeier Hanssonusability.

8:11David Heinemeier HanssonThis agent harness

8:12David Heinemeier Hanssonquestion where

8:15David Heinemeier HanssonI don't know if OPUS 4.5 was that much smarter than OPUS four, which is what we had in the summer.

8:21David Heinemeier HanssonBut its ability to

8:23David Heinemeier Hanssoninstrument your computer, to use tools, to check its own work,

8:27David Heinemeier Hanssonto

8:28David Heinemeier Hanssonapply its intelligence in such a way that you could get

8:32David Heinemeier Hanssonreal meaningful work out of it was completely different. And I think this is

8:38David Heinemeier Hanssonthen the big change that happens for almost anyone who paid attention and started playing with it over the Christmas break. This is what I heard from Shopify and other places with lots of employees who

8:48David Heinemeier Hanssonsuddenly had a breather, suddenly had a couple of weeks to lean back and just look at what was going on, gave it a try,

8:56David Heinemeier Hanssonand had the same

8:57David Heinemeier Hanssonmind blowing experience that these agents were of a different genre than what we had before.

9:05David Heinemeier HanssonAnd then what we get to is

9:08David Heinemeier HanssonI'm already excited at this point. By December,

9:12David Heinemeier HanssonI'm already revisiting

9:14David Heinemeier Hanssonsort of all my priors Mhmm. And going like, wow. If it can do this, can it also do that? Mhmm. Oh, yeah. It can.

9:20David Heinemeier HanssonAnd again, Opus four point five now

9:23David Heinemeier Hanssonlooks like a retarded model.

9:26David Heinemeier HanssonYeah. And this is the

9:28David Heinemeier Hanssonmagic of this progress is you think you've reached something. I remember thinking at the moment,

9:35David Heinemeier Hanssonif this is the last model we get, I'll be set. I'll be happy. Yep. I could live with Opus 4.5 for the next twenty years, and you would hear no complaints from me because it was just so

9:46David Heinemeier Hanssonincredibly

9:48David Heinemeier Hanssonamazing to see an agent do all this work in the way that I wanted it done because it was not just about it being able to solve a task.

9:57David Heinemeier HanssonIt was also that I could look at its