500 ERROR - deploying self-hosted Cal.com instance on Vercel using Supabase #23958
Description
Issue Summary
I deployed a self-hosted Cal.com instance on Vercel using Supabase as the Postgres database. The deployment finishes, but migrations never run. Prisma logs show it cannot find the schema file, which prevents tables from being created.
Steps to Reproduce
Forked and deployed Cal.com monorepo to Vercel.
Connected Vercel project to a new Supabase Postgres instance (via DATABASE_URL).
Set required environment variables (DATABASE_URL, NEXTAUTH_SECRET, CALENDSO_ENCRYPTION_KEY, etc.).
Deployed to production.
Navigated to the Vercel app → immediate 500 error.
Vercel build logs show warnings from Prisma:
[PrismaClientInitializationError]: Invalid prisma.user.count() invocation
Can't reach database server at <SUPABASE_URL>:5432
prisma:warn We could not find your Prisma schema in the default locations
Actual Results
Deployment succeeds, but the app throws 500 errors.
Prisma schema not detected; database migrations never applied.
Tables for Cal.com do not exist in the connected Supabase project.
Expected Results
Prisma should find the schema and run the correct migrations against the Supabase database during deployment.
After deployment, I should be able to load the dashboard without a 500 error.
Technical Details
Hosting: Vercel (Production)
Database: Supabase (Postgres 15)
Node.js version: 22.x (Vercel default)
Prisma version (from logs): 6.7.0 / 6.8.2
Browser: Chrome 139.0.0.0 (MacOS)
Related warnings:
WARNING no output files found for task @calcom/platform-constants#post-install
EMAIL_FROM environment variable is not set
Evidence
Screenshot of Vercel deployment details with 500 error.
Logs showing Prisma warnings (schema not found, can't reach database server).
Environment variables confirmed set in Vercel dashboard.
Supabase connection tested independently (direct psql connection works).