Localhost Database Connection Strings for Development

Local Development Defaults

During development, you typically connect to databases running on your local machine. Here are copy-paste ready connection strings for each database with their standard defaults.

PostgreSQL

postgresql://postgres:postgres@localhost:5432/devdb

Default installation creates a postgres superuser. Common package manager installations:

• macOS (Homebrew): brew install postgresql@16 — starts on port 5432, user postgres or your OS username
• Ubuntu/Debian: sudo apt install postgresql — user postgres, authenticate via sudo -u postgres psql
• Docker: docker run -p 5432:5432 -e POSTGRES_PASSWORD=postgres postgres:16

MySQL

mysql://root:password@localhost:3306/devdb

MySQL defaults to root user. The default password depends on installation:

• macOS (Homebrew): No password by default
• Ubuntu/Debian: Set during installation
• Docker: docker run -p 3306:3306 -e MYSQL_ROOT_PASSWORD=password mysql:8

MongoDB

mongodb://localhost:27017/devdb

MongoDB's default installation has no authentication enabled. For authenticated development:

mongodb://admin:password@localhost:27017/devdb?authSource=admin

Redis

redis://localhost:6379/0

Redis defaults to no authentication. For password-protected Redis:

redis://:mypassword@localhost:6379/0

SQLite

file:./dev.db

No server needed — just a file path. For in-memory testing:

file::memory:

MSSQL

sqlserver://sa:YourStr0ngP@ssword@localhost:1433;database=devdb;trustServerCertificate=true

SQL Server requires a strong password for the sa account (minimum 8 characters with uppercase, lowercase, and digits).

Docker Compose All-in-One

A common development setup runs all databases in Docker Compose:

services:
  postgres:
    image: postgres:16
    ports: ["5432:5432"]
    environment:
      POSTGRES_PASSWORD: postgres
  mysql:
    image: mysql:8
    ports: ["3306:3306"]
    environment:
      MYSQL_ROOT_PASSWORD: password
  mongo:
    image: mongo:7
    ports: ["27017:27017"]
  redis:
    image: redis:7
    ports: ["6379:6379"]

.env File Template

POSTGRES_URL="postgresql://postgres:postgres@localhost:5432/devdb"
MYSQL_URL="mysql://root:password@localhost:3306/devdb"
MONGO_URL="mongodb://localhost:27017/devdb"
REDIS_URL="redis://localhost:6379/0"
SQLITE_URL="file:./dev.db"