npm install @neondatabase/serverless

npm install @vercel/postgres

undefined

**For Vercel Postgres:**
```bash

**CRITICAL:**
- Use **pooled connection string** for serverless (ends with `-pooler.region.aws.neon.tech`)
- Non-pooled connections will exhaust quickly in serverless environments
- Always include `?sslmode=require` parameter

import { neon } from '@neondatabase/serverless';

const sql = neon(process.env.DATABASE_URL!);

// Simple query
const users = await sql`SELECT * FROM users WHERE id = ${userId}`;

// Transactions
const result = await sql.transaction([
  sql`INSERT INTO users (name) VALUES (${name})`,
  sql`SELECT * FROM users WHERE name = ${name}`
]);

import { sql } from '@vercel/postgres';

// Simple query
const { rows } = await sql`SELECT * FROM users WHERE id = ${userId}`;

// Transactions
const client = await sql.connect();
try {
  await client.sql`BEGIN`;
  await client.sql`INSERT INTO users (name) VALUES (${name})`;
  await client.sql`COMMIT`;
} finally {
  client.release();
}

npm install @neondatabase/serverless

npm install @vercel/postgres

undefined

**Key Points:**
- Both packages use HTTP/WebSocket (no TCP required)
- Edge-compatible (works in Cloudflare Workers, Vercel Edge Runtime)
- Connection pooling is built-in when using pooled connection strings
- No need for separate connection pool libraries

---

undefined

**CRITICAL:**
- Always use the **pooled connection string** (ends with `-pooler.region.aws.neon.tech`)
- Non-pooled connections are for direct connections (not serverless)
- Include `?sslmode=require` in connection string

---

undefined

**For Vercel Postgres:**
```bash

**For Cloudflare Workers** (wrangler.jsonc):
```json
{
  "vars": {
    "DATABASE_URL": "postgresql://user:password@ep-xyz-pooler.us-east-1.aws.neon.tech/neondb?sslmode=require"
  }
}

// scripts/migrate.ts
import { neon } from '@neondatabase/serverless';

const sql = neon(process.env.DATABASE_URL!);

await sql`
  CREATE TABLE IF NOT EXISTS users (
    id SERIAL PRIMARY KEY,
    name TEXT NOT NULL,
    email TEXT UNIQUE NOT NULL,
    created_at TIMESTAMP DEFAULT NOW()
  )
`;

// db/schema.ts
import { pgTable, serial, text, timestamp } from 'drizzle-orm/pg-core';

export const users = pgTable('users', {
  id: serial('id').primaryKey(),
  name: text('name').notNull(),
  email: text('email').notNull().unique(),
  createdAt: timestamp('created_at').defaultNow()
});

// db/index.ts
import { drizzle } from 'drizzle-orm/neon-http';
import { neon } from '@neondatabase/serverless';
import * as schema from './schema';

const sql = neon(process.env.DATABASE_URL!);
export const db = drizzle(sql, { schema });

undefined

**Option C: Prisma**
```prisma
// prisma/schema.prisma
generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider = "postgresql"
  url      = env("POSTGRES_PRISMA_URL")
}

model User {
  id        Int      @id @default(autoincrement())
  name      String
  email     String   @unique
  createdAt DateTime @default(now()) @map("created_at")

  @@map("users")
}

npx prisma migrate dev --name init

// ✅ Correct: Template tag syntax (prevents SQL injection)
const users = await sql`SELECT * FROM users WHERE email = ${email}`;

// ❌ Wrong: String concatenation (SQL injection risk)
const users = await sql('SELECT * FROM users WHERE email = ' + email);

// Automatic transaction (array of queries)
const results = await sql.transaction([
  sql`INSERT INTO users (name) VALUES (${name})`,
  sql`UPDATE accounts SET balance = balance - ${amount} WHERE id = ${accountId}`
]);

// Manual transaction with callback (for complex logic)
const result = await sql.transaction(async (sql) => {
  const [user] = await sql`INSERT INTO users (name) VALUES (${name}) RETURNING id`;
  await sql`INSERT INTO profiles (user_id) VALUES (${user.id})`;
  return user;
});

await db.transaction(async (tx) => {
  await tx.insert(users).values({ name, email });
  await tx.insert(profiles).values({ userId: user.id });
});

Pooled (serverless):     postgresql://user:pass@ep-xyz-pooler.region.aws.neon.tech/db
Non-pooled (direct):     postgresql://user:pass@ep-xyz.region.aws.neon.tech/db

// Both packages handle pooling automatically when using pooled connection string
import { neon } from '@neondatabase/serverless';
const sql = neon(process.env.DATABASE_URL!); // Pooling is automatic

// src/index.ts
import { neon } from '@neondatabase/serverless';

export default {
  async fetch(request: Request, env: Env) {
    const sql = neon(env.DATABASE_URL);
    const users = await sql`SELECT * FROM users`;
    return Response.json(users);
  }
};

undefined

**Vercel (Next.js API Route):**
```typescript
// app/api/users/route.ts
import { sql } from '@vercel/postgres';

export async function GET() {
  const { rows } = await sql`SELECT * FROM users`;
  return Response.json(rows);
}

undefined

**Test Queries:**
```bash

**Key Points:**
- Test locally before deploying
- Monitor query performance in Neon dashboard
- Set up alerts for connection pool exhaustion
- Use Neon's query history for debugging

---

import { Pool } from '@neondatabase/serverless';

const pool = new Pool({ connectionString: process.env.DATABASE_URL });

// CRITICAL: Handle connection termination errors
pool.on('error', (err) => {
  console.error('Unexpected database error:', err);
  // Implement reconnection logic or alerting
});

import { Pool, neonConfig } from '@neondatabase/serverless';

// Enable Pool queries over HTTP fetch (required for edge)
neonConfig.poolQueryViaFetch = true;

const pool = new Pool({ connectionString: env.DATABASE_URL });

export default {
  async fetch(request: Request, env: Env) {
    // Pool.query() now uses HTTP instead of WebSocket
    const result = await pool.query('SELECT * FROM users');
    return Response.json(result.rows);
  }
};

// ❌ Can timeout during prerender
import { Pool, neonConfig } from '@neondatabase/serverless';
neonConfig.poolQueryViaFetch = true;
const pool = new Pool({ connectionString: process.env.DATABASE_URL });

async function getData() {
  'use cache';
  return await pool.query('SELECT * FROM data');
}

// ✅ Works with prerender
import { neon } from '@neondatabase/serverless';
const sql = neon(process.env.DATABASE_URL!);

async function getData() {
  'use cache';
  return await sql`SELECT * FROM data`;
}

// ❌ FAILS in Node v20 with Neon driver
await db.transaction(async (tx) => {
  const [user] = await tx.insert(users).values({ name: 'Alice' }).returning();

  // Parallel inserts lose transaction context
  await Promise.all([
    tx.insert(userSettings).values({ userId: user.id, theme: 'dark' }),
    tx.insert(userSettings).values({ userId: user.id, locale: 'en' })
  ]);
  // Error: Foreign key constraint violation (user.id not visible)
});

// ✅ WORKS - Sequential execution
await db.transaction(async (tx) => {
  const [user] = await tx.insert(users).values({ name: 'Alice' }).returning();

  await tx.insert(userSettings).values({ userId: user.id, theme: 'dark' });
  await tx.insert(userSettings).values({ userId: user.id, locale: 'en' });
});

// ✅ ALTERNATIVE - Use postgres-js driver for Node.js (not edge-compatible)
import { drizzle } from 'drizzle-orm/postgres-js';
import postgres from 'postgres';
const client = postgres(connectionString);
const db = drizzle(client);
// Promise.all() works correctly with this driver

const result = await sql("SELECT * FROM users WHERE id = $1", [userId]);

// Option 1: Tagged template (recommended)
const result = await sql`SELECT * FROM users WHERE id = ${userId}`;

// Option 2: .query() method for parameterized queries
const result = await sql.query("SELECT * FROM users WHERE id = $1", [userId]);

// Option 3: .unsafe() for trusted raw SQL (dynamic identifiers)
const column = 'name';
const result = await sql`SELECT ${sql.unsafe(column)} FROM users`;

This function can now be called only as a tagged-template function:
sql`SELECT ${value}`, not sql("SELECT $1", [value], options)

{
  "dependencies": {
    "@neondatabase/serverless": "^1.0.2",
    "better-auth": "^1.3.4",
    "drizzle-orm": "^0.40.1"
  }
}

import { Kysely } from 'kysely';
import { Pool } from '@neondatabase/serverless';

const db = new Kysely({
  dialect: new PostgresDialect({
    pool: new Pool({ connectionString: process.env.DATABASE_URL })
  })
});

// HTTP: Best for single queries
import { neon } from '@neondatabase/serverless';
const sql = neon(env.DATABASE_URL);
const users = await sql`SELECT * FROM users`; // ~37ms

// WebSocket: Best for multiple sequential queries
import { Pool } from '@neondatabase/serverless';
const pool = new Pool({ connectionString: env.DATABASE_URL });
const client = await pool.connect(); // ~15ms setup
try {
  const user = await client.query('SELECT * FROM users WHERE id = $1', [1]); // ~5ms
  const posts = await client.query('SELECT * FROM posts WHERE user_id = $1', [1]); // ~5ms
  const comments = await client.query('SELECT * FROM comments WHERE user_id = $1', [1]); // ~5ms
  // Total: ~30ms (vs ~111ms with HTTP)
} finally {
  client.release();
}

{
  "dependencies": {
    "@neondatabase/serverless": "^1.0.2"
  }
}

{
  "dependencies": {
    "@vercel/postgres": "^0.10.0"
  }
}

{
  "dependencies": {
    "@neondatabase/serverless": "^1.0.2",
    "drizzle-orm": "^0.44.7"
  },
  "devDependencies": {
    "drizzle-kit": "^0.31.7"
  },
  "scripts": {
    "db:generate": "drizzle-kit generate",
    "db:migrate": "drizzle-kit migrate",
    "db:studio": "drizzle-kit studio"
  }
}

import { defineConfig } from 'drizzle-kit';

export default defineConfig({
  schema: './db/schema.ts',
  out: './db/migrations',
  dialect: 'postgresql',
  dbCredentials: {
    url: process.env.DATABASE_URL!
  }
});

import { neon } from '@neondatabase/serverless';

interface Env { DATABASE_URL: string; }

export default {
  async fetch(request: Request, env: Env) {
    const sql = neon(env.DATABASE_URL);
    const users = await sql`SELECT * FROM users`;
    return Response.json(users);
  }
};

'use server';
import { sql } from '@vercel/postgres';

export async function getUsers() {
  const { rows } = await sql`SELECT * FROM users`;
  return rows;
}

// db/index.ts
import { drizzle } from 'drizzle-orm/neon-http';
import { neon } from '@neondatabase/serverless';
import * as schema from './schema';

const sql = neon(process.env.DATABASE_URL!);
export const db = drizzle(sql, { schema });

// Usage: Type-safe queries with JOINs
const postsWithAuthors = await db
  .select({ postId: posts.id, authorName: users.name })
  .from(posts)
  .leftJoin(users, eq(posts.userId, users.id));