How I Built an Instagram API That AI Agents Pay For (x402 + FastAPI + MCP)

The Problem: APIs Assume Humans Most APIs are designed for human developers -- you, get an API key, set up billing, and manage credentials. But AI agents don't have credit cards or email inboxes. They're scripts that run autonomously, sometimes thousands of times per day. I wanted to build something different: an API where AI agents are the first-class customer, not an afterthought. What I Built Social Intel API is an Instagram influencer search endpoint with one unusual property: it accepts USDC micropayments instead of API keys.