PostgreSQL is an advanced, enterprise-class open-source relational database that supports both SQL (relational) and JSON (non-relational) querying. It is a highly stable database management system backed by more than 20 years of community development.
PostgreSQL is a server-based database system.
Note: PostgreSQL runs as a service (background process) that’s always running on your system. Your applications connect to it via network (even though it’s on the same computer)
PostgreSQL VS. MySQL
PostgreSQL is built for extensibility and advanced features, while MySQL is built for speed and simplicity in traditional web applications.