MCP PostgreSQL Server (Stateful and Dual Transport)
A Model Context Protocol (MCP) server that provides both HTTP and Stdio transports for interacting with PostgreSQL databases. This server exposes database resources and tools through both transport methods, allowing for flexible integration in different environments.
Features
- Dual Transport Support: Both HTTP (StreamableHTTPServerTransport) and Stdio (StdioServerTransport)
- Database Resources: List tables and retrieve schema information
- Query Tool: Execute read-only SQL queries
- Stateful Sessions: HTTP transport supports session management
- Docker Support: Containerized deployments for both transports
- Production Ready: Graceful shutdown, error handling, and logging
Quick Start
Environment Setup
The database credentials must be passed as:
- Either environment variables
# PostgreSQL Database Connection String
export POSTGRES_URL=your_connection_string
# PostgreSQL Database Configuration if POSTGRES_URL is not provided
export POSTGRES_USERNAME=your_username
export POSTGRES_PASSWORD=your_password
export POSTGRES_HOST=localhost
export POSTGRES_PORT=5432 # this is the default
export POSTGRES_DATABASE=your_database
# HTTP Server Configuration
# Following are the default values
export PORT=3000
export HOST=0.0.0.0
# CORS Configuration (comma-separated list of allowed origins)
# Following are the default values
export CORS_ORIGIN=http://localhost:8080,http://localhost:3000
# Environment
# Following are the default values
export NODE_ENV=development
- Or in the working directory (directory where
npxcommand will be run): create a.envfile (the package usesdotenvpackage)
# .env.example
# PostgreSQL Database Configuration
POSTGRES_USERNAME=your_username
POSTGRES_PASSWORD=your_password
POSTGRES_HOST=localhost
POSTGRES_DATABASE=your_database
# HTTP Server Configuration
PORT=3000
HOST=0.0.0.0
# CORS Configuration (comma-separated list of allowed origins)
CORS_ORIGIN=http://localhost:8080,http://localhost:3000
# Environment
NODE_ENV=development
Run using npx
- Download node.js and npm from here
- Run the package. By default, it will run streamable http on port 3000:
npx @ahmedmustahid/postgres-mcp-server
# or npx @ahmedmustahid/postgres-mcp-server --port 3000 --verbose
- For stdio transport:
npx @ahmedmustahid/postgres-mcp-server stdio
# npx @ahmedmustahid/postgres-mcp-server stdio --verbose
Environment Setup
Copy environment template
cp .env.example .env
Edit your database credentials
nano .env
Podman(or Docker) Usage
- Install podman from here
- Install
uvfrom here - Install podman compose package:
uv add podman-compose(oruv syncto sync packages inpyproject.toml)
#get the environment variables
set -a
source .env
set +a
podman machine start
make podman-up
Test using Claude Desktop
First, install node.js and npm, build the project following the above instructions.
Edit your claude_desktop_config.json
{
"mcpServers": {
"postgres-mcp-server": {
"command": "npx",
"args": [
"@ahmedmustahid/postgres-mcp-server",
"stdio"
],
"env": {
"POSTGRES_USERNAME": "your-username",
"POSTGRES_PASSWORD": "your-password",
"POSTGRES_HOST": "hostname",
"POSTGRES_DATABASE": "database-name"
}
}
}
}
Check if MCP Server has been enabled
Verify from Claude Desktop Window
Using MCP Server from Claude Desktop
Prompt: Show sales table from last year.
Test using MCP Inspector
First, install node.js and npm, build the project following the above instructions. Install MCP Inspector: instructions: here
Check Stdio MCP Server
npx @modelcontextprotocol/inspector npx @ahmedmustahid/postgres-mcp-server stdio
Check Streamable HTTP MCP Server
First, run the server (shell where environment has been configured):
npx @ahmedmustahid/postgres-mcp-server
Run the mcp inspector from another terminal
npx @modelcontextprotocol/inspector
After selecting Streamable HTTP from drop down menu, insert http://localhost:3000/mcp(default) into URL.
MCP tools:
MCP Resource:
Configuration
Environment Variables
You have to specify these inside the .env file.
| Variable | Description | Default | Required |
|---|---|---|---|
POSTGRES_USERNAME | PostgreSQL username | - | Yes |
POSTGRES_PASSWORD | PostgreSQL password | - | Yes |
POSTGRES_HOST | PostgreSQL host | - | Yes |
POSTGRES_DATABASE | PostgreSQL database name | - | Yes |
PORT | HTTP server port | 3000 | No |
HOST | HTTP server host | 0.0.0.0 | No |
CORS_ORIGIN | Allowed CORS origins (comma-separated) | localhost:8080,localhost:3000 | No |
NODE_ENV | Environment mode | development | No |
Resources
Hello World (hello://world)
A simple greeting message for testing.
Database Tables (database://tables)
Lists all tables in the public schema with their schema URIs.
Database Schema (database://tables/{tableName}/schema)
Returns column information for a specific table.
Tools
query
Execute read-only SQL queries against the database.
Parameters:
sql(string): The SQL query to execute
Transport Differences
| Feature | HTTP Transport | Stdio Transport |
|---|---|---|
| Session Management | ✅ Stateful sessions | ❌ Stateless |
| Concurrent Connections | ✅ Multiple clients | ❌ Single process |
| Web Integration | ✅ REST API compatible | ❌ CLI only |
| Interactive Use | ✅ Via HTTP clients | ✅ Direct stdio |
| Docker Deployment | ✅ Web service | ✅ CLI container |
Health Checks
The HTTP server includes a basic health check endpoint accessible at the /health endpoint with a GET request (returns 405 Method Not Allowed, confirming the server is responsive).
Troubleshooting
Common Issues
-
Database Connection Errors
# Check your database credentials in .env # Ensure PostgreSQL is running and accessible -
Port Already in Use
# Change PORT in .env or stop conflicting services lsof -i :3000 -
Docker Build Issues
# Clean Docker cache npm run docker:clean docker system prune -a -
Session Management (HTTP)
# Sessions are stored in memory and will reset on server restart # For production, consider implementing persistent session storage
Development
Adding New Resources
- Create a new file in
src/resources/ - Implement the resource registration function
- Add it to
src/server/server.ts
Adding New Tools
- Create a new file in
src/tools/ - Implement the tool registration function
- Add it to
src/server/server.ts
License
MIT
Contributing
Please read the contributing guidelines and submit pull requests to the main repository.