Hopper

Aayush Naik is building the first agentic dev environment for mainframe and COBOL — which sounds unhinged until you realize there are fewer than 2,000 COBOL developers left on Earth and every single bank, insurer, and government agency still runs on this garbage. His YC-backed startup Hypercubic just raised to solve the modernization problem these legacy systems created, and honestly? This is either a sleeper hit or a graveyard. The market is tiny, the customers are massive enterprises who change nothing for decades, and the dev tooling is essentially nonexistent. But if they nail it, every Fortune 500 is locked in. The vibe is "boring infrastructure that only matters until it matters a whole lot."