Beginners

1 Servers.

2 Operating System.

3 Server-side Programming Language.

4 Framework.

5 Git and GitHub.

Intermediate
Intermediate

Databases

1 API and API Design.

2 Software Testing.

3 Software Design Principles.

4 Web Security.

5 Algorithms.

Advanced

1 Scalability.

2 Deployment.

3 Caching and CDNs.

4 Message Brokers.

5 Search Engines.

6 Containerization and CI/CD.

7 Deployment.