Building APIs for the Age of Agentic Engineering

📝 On APIs When I started angel investing my thesis was: the best companies are going to start out as APIs. I went on to seed invest in Scale AI, called scaleapi.com at the time, the API to human intelligence. Auth0, the API to identity. Clearbit, the API to business data. cc @vcbrags. Why was "API" a thesis? React was coming out, the idea of Next.js & Vercel was forming in my mind. The best software is the one that works for you, represents you, looks like you. Off-the-shelf software was "worst-common-denominator" software. The barrier to entry to building your own software would collapse with the rise of frameworks and cloud infrastructure. Building on that early success, my advice to aspiring entrepreneurs became: just build the API. Make your / homepage the description of that API. Focus on problems where a simple API can hide enormous amounts of real-world and business complexity. (Incidentally this advice works extra-well because it helps founders focus and not over-build.) Fast forward to the age of AI, agentic engineering, and the SaaS public market bloodbath. Software is now free to build. But when you sit down to vibe code your next 25k/mo MRR app with no mistakes, that app will sit on the shoulders of giants. Your agent will read Markdown. Then, it will run CLIs and call MCP tools. Your software will make API calls to other services. And software will become more and more invisible. Computers talking to other computers to get you an answer, even before you ask. If you're starting now (or starting over), focus on the API. Do it for the agents. http://x.com/i/article/20220407149397073…