Node.js + @neondatabase/serverless: supply the ws constructor

Node.js + serverless driver: set the WebSocket constructor

The trap

@neondatabase/serverless speaks WebSockets, and Node.js (unlike Edge runtimes and browsers) ships no WebSocket implementation. new Pool({ connectionString }) then pool.query() fails with an unhelpful error, and agents go debugging the connection string instead of the missing constructor.

The rule (from the driver docs)

import { Pool, neonConfig } from '@neondatabase/serverless';
import ws from 'ws';
neonConfig.webSocketConstructor = ws;

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

• npm install ws (and @types/ws for TypeScript).
• Set neonConfig.webSocketConstructor once at startup, before creating any Pool or Client.
• Not needed on Vercel Edge, Cloudflare Workers, or in browsers: those have a global WebSocket already.
• Not needed for the neon() HTTP client: it uses fetch, not WebSockets.

Checklist

• If the driver fails only in Node and works on Edge, this is the cause.
• Keep ws out of Edge bundles; gate the import to Node runtime code paths.