nextjs-better-auth-postgres-docker

Next.js + Better Auth + PostgreSQL + Docker

This is a skill for building Next.js App Router + Better Auth + PostgreSQL with Docker and deploying to Cloud Run.

Target Stack

• Framework: Next.js (App Router, TypeScript)
• Authentication: Better Auth
• DB: PostgreSQL 16
• Package manager: pnpm
• Infrastructure: Docker / Docker Compose、Google Cloud Run、Cloud SQL、Secret Manager

Reference Documents

Detailed procedures are split into the following reference files.

File	Content
references/local-setup.md	Building the local development environment (Docker Compose + app Dockerization)
references/cloud-run-deploy.md	Deploying to Cloud Run (using Cloud SQL + Secret Manager)

Which One to Refer To

• Want to build the local environment → references/local-setup.md Read
• I want to deploy to Cloud Run → references/cloud-run-deploy.md Read
• Want to do both → local-setup.md Complete cloud-run-deploy.md then proceed to

Summary of Environment Variable Switching

Keep track of the variables whose values change depending on the execution environment.

Variable Name	Local Direct Execution	Docker Compose (app container)	Cloud Run
DATABASE_URL host	localhost	db	Cloud SQL Unix socket
BETTER_AUTH_URL	http://localhost:3000	http://localhost:3000	Cloud Run service URL
INTERNAL_API_BASE_URL	http://localhost:3000	http://app:3000	Cloud Run service URL