Using Prisma Client in a Next.js project in a monorepo setup

Problem

If you use Prisma Client in a Next.js application within a monorepo, you may run into an error that looks similar to:

Prisma Client could not locate the Query Engine for runtime "debian-openssl-3.0.x".

We detected that you are using Next.js, learn how to fix this: https://pris.ly/d/engine-not-found-nextjs.

This is likely caused by tooling that has not copied "libquery_engine-debian-openssl-3.0.x.so.node" to the deployment folder.
Ensure that you ran \`prisma generate\` and that "libquery_engine-debian-openssl-3.0.x.so.node" has been copied to "generated/client".

We would appreciate if you could take the time to share some information with us.
Please help us by answering a few questions: https://pris.ly/engine-not-found-tooling-investigation

or:

Prisma Client could not locate the Query Engine for runtime "debian-openssl-3.0.x".

We detected that you are using Next.js, learn how to fix this: https://pris.ly/d/engine-not-found-nextjs.

This is likely caused by a bundler that has not copied "libquery_engine-debian-openssl-3.0.x.so.node" next to the resulting bundle.
Ensure that "libquery_engine-debian-openssl-3.0.x.so.node" has been copied next to the bundle or in "generated/client".

We would appreciate if you could take the time to share some information with us.
Please help us by answering a few questions: https://pris.ly/engine-not-found-bundler-investigation

Assume you have a monorepo with the following structure:

.
├── packages
│   ├── db
│   │   ├── index.ts
│   │   ├── node_modules
│   │   ├── package.json
│   │   └── prisma
│   │       ├── client // <-- Custom output location for the generated Prisma Client
│   │       │   ├── index.js
│   │       │   ├── libquery_engine-debian-openssl-1.1.x.so.node // engine to be copied
│   │       │   └── schema.prisma // schema to be copied
│   │       └── schema.prisma
│   └── service/
│       ├── pages/
│       │   └── api/
│       │       └── test.js
│       ├── next.config.js
│       └── package.json
├── pnpm-workspace.yaml
├── package.json
└── vercel.json

The file tree above shows a monorepo contained in a packages folder. Inside, there are two packages:

• db: Contains the generated Prisma Client in a custom output location named client. index.ts at the root of this package exports the instantiated Prisma Client.
• service: Contains a Next.js application. The test.js API route uses the Prisma Client instance provided by the db package.

The errors mentioned above occur as a result of a bundling problem during Next.js's bundling process. The Query Engine file(s) is expected to be found next to the generated Prisma Client. The bundling process, however, does not copy over those files to the output location of the bundle.

info

For a more detailed explanation of exactly what is going wrong during the bundling process, please refer to this issue we opened in the Next.js GitHub repository.

Solution

To work around this issue, you can use a custom Webpack plugin we created that correctly copies the files Prisma Client needs to their correct location.

To use this plugin, first install the package:

npm install -D @prisma/nextjs-monorepo-workaround-plugin

You can then import the plugin into your next.config.js file and use it in config.plugins. For example:

const { PrismaPlugin } = require('@prisma/nextjs-monorepo-workaround-plugin')

module.exports = {
  webpack: (config, { isServer }) => {
    if (isServer) {
      config.plugins = [...config.plugins, new PrismaPlugin()]
    }

    return config
  },
}