... first. I built Sharpread, a forensic SEC filing analysis tool, on a standard in-process rate limiter for managing requests to the SEC EDGAR database. It worked perfectly in development and in early production. Then I hit a wall. Vercel's serverless architecture spins up multiple Lambda instances concurrently. Each instance had its own rate limiter. They had no idea the others existed. Under any real traffic spike, the instances collectively hammered EDGAR