How I Resolved Prisma Issues and Fixed Vercel 500 INTERNAL_SERVER_ERROR 🚀

Yesterday, I moved an old application from my own hosting to Vercel. Although I anticipated some challenges, I encountered an issue that took longer to resolve than expected. Here’s how I navigated the problem and found a solution, so you can save time if you face the same problem! 😊

Step 1: Update Prisma and @prisma/client

First, make sure you are using the latest versions of Prisma and @prisma/client. For my project, the latest version at the time was 5.14.0. Run the following command to update them:

npm install prisma@5.14.0 @prisma/client@5.14.0 --save-dev

Step 2: Initial Setup

After deploying to Vercel, I noticed the following error in Vercel's logs:

Prisma has detected that this project was built on Vercel, which caches dependencies.
This leads to an outdated Prisma Client because Prisma's auto-generation isn't triggered.
To fix this, make sure to run the `prisma generate` command during the build process.

Learn how: https://pris.ly/d/vercel-build

Step 3: Following the Instructions

The error message was clear. To fix it, I needed to add the following to my package.json:

"postinstall": "prisma generate"

Step 4: Adding a Build Command

However, this didn't completely resolve the issue. So, I updated Vercel's build command to ensure Prisma generates the client before building the application:

"build": "npx prisma generate && next build"

Step 5: Encountering a New Issue

After this change, my application built successfully, but all API calls returned a Vercel 500: INTERNAL_SERVER_ERROR. This was frustrating, and there wasn’t much information available on how to fix it. 😤

Step 6: Debugging the Problem

After a few hours of trial and error, I found the problem in my schema.prisma file. Here’s what my initial setup looked like:

generator client {
  provider      = "prisma-client-js"
  binaryTargets = ["native", "linux-musl"] // <- Required on Ubuntu
}

datasource db {
  provider     = "postgresql"
  url          = env("DATABASE_URL")
  relationMode = "prisma"
}

This setup worked fine on my server but caused issues on Vercel as I forgot it was customed specificlly for Ubuntu.

Step 7: Correcting the Schema

Here are the correct settings:

generator client {
  provider      = "prisma-client-js"
  previewFeatures = ["driverAdapters"] // <- neon.tech
}

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

Step 8: Sleep

With these adjustments, my application ran smoothly on Vercel. Finally, I could get some well-deserved rest! 🎉

I hope this will save someone time! ⏳