Build Your Own PostgreSQL MCP Server

This n8n workflow demonstrates how to build a simple yet powerful PostgreSQL MCP (Model Context Protocol) server. It uses an MCP server trigger connected to five tools: two read-only PostgreSQL nodes for basic queries and three custom workflow tools for select, insert, and update operations. The custom tools enforce a restricted input schema to prevent unsafe raw SQL, constructing statements safely within the workflow. All custom operations route through a shared 'Execute Workflow' trigger with a switch node to direct to the appropriate PostgreSQL handler, ensuring responses are returned to the MCP client.

Key benefits include enhanced security by avoiding direct SQL injection risks, seamless integration with MCP-compatible clients like Claude Desktop, and flexibility for business database management. It's based on the official MCP PostgreSQL reference implementation, making it reliable and extensible.

Ideal use cases: Automate HR record updates, payroll processing, sales tracking, inventory management, or any PostgreSQL-backed operations via AI agents. Setup requires a PostgreSQL database; connect clients per n8n docs and test with sample queries for quick wins in productivity and data ops.