Give agents what they want. Start with APIs.
Over the past two months, something happened that I’ve never seen before. The biggest names in tech started saying the same thing, independently, across podcasts, X threads, LinkedIn posts, and long-form essays. Not coordinated. Not prompted. Just… convergent.
They all said APIs matter. Not as plumbing. As strategy.
Let me walk you through what I saw.
It started with Sam Altman
In February, Altman dropped this line in a TBPN Live interview: “…every company is an API company now, whether they want to be or not”.
Not “tech companies”. Not “developer platforms”. Every company.
Then he followed up on X: OpenAI added more than $1B of ARR in a single month from the API alone. Not for ChatGPT, just the API. When the CEO of the most talked-about AI company says the API is the growth engine, that’s not a technical detail. That’s a strategic signal.
Dario Amodei, CEO of Anthropic, said on the Dwarkesh Patel podcast: “I actually do think that the API model is more durable than many people think”. His argument: exponential technology progress creates a continuous surface area of new use cases. My take: The API isn’t an interface. It’s the business model, the endgame.
This was already kind of obvious, the foundation model companies are API-first, but what convinced me was their conviction on the business model.
Guillermo Rauch, who created Next.js and runs Vercel, posted an entire X article titled “On APIs”. His thesis: “The best companies are going to start out as APIs”. He’d seed-invested in Scale AI, Auth0, Clearbit, all API-first companies. His advice to anyone starting now: “Focus on the API. Do it for the agents”.
Aaron Levie, CEO of Box, wrote a long-form essay called “Building for trillions of agents”. His line was the most direct: “If you don’t have an API for a feature, it might as well not exist”. And in a reply to Andrej Karpathy, says “Products without comprehensive APIs or CLIs will just slowly die off. The forces are just too strong on this one”.
Karpathy reacted to Levie’s essay with an iconic image of a claw army marching toward giant golden letters spelling “API”. Agents praying for APIs?
His words: “Every business you go to is still so used to giving you instructions over legacy interfaces. They expect you to navigate to web pages, click buttons, they give out instructions for where to click and what to enter here or there. This suddenly feels rude. Why are you telling me what to do? Please give me the thing I can copy paste to my agent”.
What they’re all saying is, be API-first, that’s where the money and growth is.
It’s not just the CEOs
Jared Friedman from Y Combinator put it bluntly on the Lightcone podcast: “Agents hate using websites. They want to use APIs. They want to write code”. YC’s Spring 2025 batch had 67 out of 144 startups focused on AI agents. They see agents as the biggest opportunity since mobile. I kind of agree - agents will use your website, but they might miss data or waste tokens trying to figure it out.
Peter Yang, product lead at Roblox and author of one of the biggest product newsletters out there, wrote a deep dive arguing that AI agents will be your product’s first users, not humans. His 5 steps to build for agents? Get the API right first. MCP comes last, not first. He tweeted: “Your goal in the AI agent era should be to get user time spent with your product to 0 because you’ve made it so incredibly easy for agents to get work done via APIs/skills/MCPs”.
Aakash Gupta mapped the entire agent access stack across 10 companies: Stripe, Cloudflare, GitHub, Shopify, Zapier. Every layer, MCP, CLI, Skills, OpenAPI, is a wrapper or enhancement. The foundation? “Your API is always the foundation. MCP servers call it under the hood. CLIs call it under the hood. If your API is a mess, everything above it will be too”.
Abhishek Katiyar, a product leader at Amazon, connected the dots for PMs specifically: “I think every PM, not just AI PMs, should be learning about good API design right now. The product interface is shifting from ‘humans to apps’ to ‘humans to agents to apps’”.
These product builders are saying, get a great API foundation under your product and everything else including MCP has a chance of being solid.
Then the non-tech voices showed up
Greg Isenberg, a founder and podcaster, said recently: “In the old way of SaaS tools, an API was a nice to have. Now the nice to have is actually the UI”.
In the same episode, Cody Schneider, a growth operator, said he’s buying software based on API quality and literally churning products when the API doesn’t match the UI. His exact words: “There’s a thing you can do in their UI that I can’t do in their API. I’m literally about to churn because this is critical for me and now it feels archaic for me to go and interact with your fucking UI to do this outcome”. Then he goes on to say that Salesforce might be a worse product overall than HubSpot, but he’ll use it instead because it’s got a more robust API. The value is in being able to automate it.
Tim Ferriss, the ultimate automator and optimizer, on episode 859 of his show, told his 1.8 million subscribers: “The API key is a really important component to all of this”. Tim Ferriss isn’t a developer. He’s explaining to a mainstream audience that API keys unlock what agents can do.
This matters because the operators are now saying, they won’t consider your product unless they can drive it through an agent with APIs. Programmatic access becomes a buyer criterion.
Ben Tossell, who runs one of the biggest AI newsletters, summarized it in three lines: “Agents are the software market from now on. Build something agents choose. CLI/API first”.
And finally, my friend Brandur Leach, who’s been building APIs at Heroku and Stripe, wrote a beautiful essay called “The Second Wave of the API-first Economy”. His take: the first wave of APIs died because of abuse, monetization pressure, and privacy concerns. But now, APIs are coming back, not for third parties to build on your platform, but for agents acting on behalf of users. “The convention of the future will be human language, fed into what looks a lot like a terminal, and fulfilled via API”.
Why this matters to you
If you’re reading this, you probably don’t need convincing. You already know APIs are important as the ultimate expression of product value. You’ve known it for years.
But your boss might need convincing. Your VP might need a slide. Your stakeholders might need to hear it from someone other than you.
So I collected every quote from this essay, and more, into a single markdown file on GitHub. It’s organized by theme, with source links for every quote. It’s open source and you can contribute to it.
Point your AI agent at the file and say “use this to make my case”. It will pull the right quotes for your argument, whether you’re pitching an API strategy, justifying an investment, or giving a conference talk.
Here it is: https://github.com/paraskakis/chest
Open the chest. Use the loot. Win your next budget meeting.
And if you’ve been fighting the API fight for years, know this: you were right. The rest of the world just caught up.