1. Collaboration Tools (Linear, MS Teams, Slack, Zoom, Confluence) 2. Programming Languages (Java, JavaScript, Python, C#, Go) 3. API Development (REST, gRPC, Security, Encryption, Signing, Protocols) 4. Web Services (Nginx, Tomcat) 5. Cloud (AWS, Azure, Kubernetes) 6. Authentication (Tokens, OAuth2.0, JWT, Cookies) 7. Testing (TDD, Unit Test, E2E Test, Performance Testing) 8. Databases (Relational: MySQL, PostgreSQL; Non-Relational: MongoDB, Cassandra, Redis) 9. CI/CD (Jenkins, GitHub Actions, CircleCI, GitLab) 10. System DesignProtocols: TCP, UDP, DNS, Caching, Content Delivery Networks, Microservices Messaging, Architecture, Load Balancing, Sharding, Distributed Systems, Database Replication 11. Data Structures and Algorithms (Big O Notation, Recursion, Sorting, Trees, Graphs) 12. Design Patterns (Factory, Dependency Injection, Proxy, Observer, Facade) 13. AI Tools (Claude, ChatGPT, Prompt Engineering, Cursor Where are you in your journey?