Which approach is most effective for addressing scalability issues with a legacy application?

Implementing microservices is the most effective approach for addressing scalability issues with a legacy application because it allows for the decomposition of the application into smaller, independent services that can be developed, deployed, and scaled individually. This modular approach contrasts with a monolithic architecture, where all components are tightly integrated, making scalability more challenging since scaling up requires the entire application to be scaled rather than specific components.

With microservices, teams can focus on optimizing performance and scaling for each individual service based on the specific usage and demand, which supports agility and responsiveness to changing business needs. Furthermore, microservices facilitate the use of different technologies and frameworks for each service, enabling the organization to leverage the best tools available for each functional area. This architecture also fosters better resource utilization and can lead to improved fault isolation, ultimately enhancing the overall reliability and performance of the application.

In contrast, while refactoring a monolithic application may improve its structure, it often does not fundamentally address scalability issues and may still suffer from the same limitations inherent in a single, large codebase. Maintaining the current infrastructure and scaling up can lead to inefficiencies and limit flexibility, as scaling up often involves investing in more powerful hardware rather than addressing underlying architectural challenges. Relying on a third-party application