Next.js + Prisma

Environment

DATABASE_URL="postgres://user:password@host:6432/db?sslmode=require"
DIRECT_URL="postgres://user:password@host:5432/db?sslmode=require"

capydb link writes exactly this when it detects Prisma — DATABASE_URL points at the pooled endpoint and DIRECT_URL at the direct one. If you deploy on Vercel with the Vercel integration, the pushed names are DATABASE_URL (pooled) and DATABASE_URL_UNPOOLED (direct); map directUrl accordingly.

Prisma schema

datasource db {
  provider  = "postgresql"
  url       = env("DATABASE_URL")
  directUrl = env("DIRECT_URL")
}

url is what Prisma Client uses at runtime — pooled, safe for serverless. directUrl is what prisma migrate and prisma db push use — direct, because migrations need session-level features the transaction pooler does not provide.

Run it

npx prisma migrate dev    # uses DIRECT_URL
npx prisma studio         # uses DIRECT_URL
next dev                  # app traffic over DATABASE_URL

Pitfalls

• Migrations against the pooled URL fail in confusing ways (advisory lock errors, prepared statement errors). Always set directUrl.
• Serverless connection storms: Prisma Client per-invocation on the direct URL exhausts the plan's connection budget fast. The pooled URL exists for exactly this.
• Preview deployments: a preview database has its own pair of URLs. The Vercel integration scopes them to the git branch automatically; with the GitHub Action they are exported into the workflow env.