## What was reported

Issue neondatabase/serverless#15 (closed, 12 comments): 

I'm getting the following error when using this on vercel

```
Unhandled Promise Rejection 	{"errorType":"Runtime.UnhandledPromiseRejection","errorMessage":"Error: All attempts to open a WebSocket to connect to the database failed. If using Node, please install the `ws` package (or simply use the `pg` package instead).","reason":{"errorType":"Error","errorMessage":"All attempts to open a WebSocket to connect to the database failed. If using Node, please install the `ws` package (or simply use the `pg` package instead).","stack":["Error: All attempts to open a WebSocket to connect to the

## The verified resolution

[jawj (maintainer)]: On Vercel's non-Edge serverless functions the WebSocket transport may fail to open; in that environment just use ordinary node-postgres (`pg`) instead of the serverless driver. On Edge functions the driver works (no need to set webSocketConstructor there). Local `npx vercel dev` was also updated to support both. No driver bug  -  environment limitation.