Key Points

• Monolithic architecture: the entire application runs as a single process/container. Simpler for small apps, but harder to scale and maintain as complexity grows.
• Microservices architecture: the application is split into smaller, focused services. Each service does one job well and works together with others to form the full application.

Docker Compose is the tool that makes multi-container microservice deployments practical. It uses a configuration file to describe all containers, networks, and storage together.

Example microservices breakdown for a web app:

• Database — stores application data
• API — handles backend business logic
• Auth service — manages authentication and authorisation
• Web frontend — serves the user interface