Why we migrated our Next.js App Router API routes to connection-pooled MySQL and saved 60% latency

When scaling concurrent users on serverless endpoints, opening fresh database connections on every serverless lambda invocation quickly hits the max_connections limit. We implemented a singleton pool with 10 connection limits and keepAlive=true. Average query times dropped from 180ms to 8ms. If anyone is running into connection exhaustion with MySQL2 or Prisma on Vercel, feel free to ask questions here!