What are the advantages and disadvantages of microservices and monolithic architecture? Where to use each?

Monolithic Architecture

Pros:

• Simplicity of development and deployment, especially at the start of the project.
• Easier to ensure data integrity and transactions.
• Less overhead for inter-process communication.

Cons:

• Difficulty in scaling individual parts of the application.
• Harder to implement new technologies for specific modules.
• As the codebase grows, maintenance and testing become more complex.

Microservices Architecture

Pros:

• Scalability of individual services as needed.
• Flexibility in choosing technologies for each service.
• Improved error isolation — failure of one service does not break the entire product.
• Convenience for team collaboration — different teams can work on different services.

Cons:

• Complexity in organizing interaction between services (network communication, data consistency).
• Increased infrastructure requirements (containers, orchestration).
• Difficulties with debugging and monitoring a distributed system.

Where to use?

• Monolithic is suitable for small projects, startups, where speed of development and simplicity are important.
• Microservices are justified in large, scalable systems with distributed teams and requirements for high availability and flexibility.