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Database & ORM · Developer Error Resolution Lab

Fix Prisma P1001: 'Can't reach database server at host:port'

Troubleshoot network connectivity, SSL certificates, wrong port mappings, and environment variable issues with Prisma ORM.

Triggered Error Message:

PrismaClientInitializationError: Can't reach database server at `localhost`:`5432` (P1001)

Customize Solution for Your Environment
# Test TCP port connection:
nc -zv db 5432

# If using Docker Compose, ensure both services share the same network:
# services:
#   web:
#     environment:
#       - DATABASE_URL=postgresql://user:pass@db:5432/production_db?schema=public
#     depends_on:
#       db:
#         condition: service_healthy

Root Cause & Mechanism Analysis

Why does this error occur?

Database container is not running, incorrect hostname (using `localhost` instead of Docker container name or `host.docker.internal`), or missing SSL flags (`sslmode=require`).

Frequently Asked Questions

How to connect from Docker container to host machine?
On Linux/macOS/Windows, use `host.docker.internal` instead of `localhost`.
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