Solid Design vs 12 Factor App

"Solid" (SOLID) is a set of design principles for writing maintainable and scalable software. It was introduced by Robert C. Martin in the early 2000s and has since become a popular approach to software design. The SOLID principles include:

1. Single Responsibility Principle (SRP)
2. Open/Closed Principle (OCP)
3. Liskov Substitution Principle (LSP)
4. Interface Segregation Principle (ISP)
5. Dependency Inversion Principle (DIP)

On the other hand, the "12 Factor App" methodology is a set of best practices for building software-as-a-service (SaaS) applications that run in the cloud. It was first described by Adam Wiggins in 2011 and is widely adopted by developers building web applications. The 12 factors are:

1. Codebase
2. Dependencies
3. Config
4. Backing services
5. Build, release, run
6. Processes
7. Port binding
8. Concurrency
9. Disposability
10. Dev/prod parity
11. Logs
12. Admin processes

Both SOLID and the 12 Factor App methodology provide guidelines for building maintainable and scalable software, but they approach the problem from different angles. SOLID focuses on design principles for writing maintainable and scalable code, while the 12 Factor App methodology provides a set of best practices for building scalable and maintainable web applications that are deployed in the cloud.