Startups.RIP: Startups.RIP is a comprehensive research platform and wiki featuring over 1,700 Y Combinator startups that have either shut down or been acquired. It utilizes an AI research agent to provide detailed post-mortems explaining what these companies built, why they failed, and what has changed in the market since then. For active builders, it offers 'rebuild playbooks' and implementation-ready technical specifications that can be directly used with AI coding agents like Claude Code or Cursor to iterate on validated market ideas with a fresh perspective.