In which cases is it advisable to combine microservices into a monolithic architecture?

Consolidating microservices into a monolithic architecture may be appropriate in the following cases:

• Management complexity of microservices exceeds the benefits: if the number of microservices is small and their interactions are too tight, supporting a distributed system becomes unnecessarily complex.
• Lack of resources for infrastructure support: microservices require separate deployment, monitoring, and scaling. If the team or infrastructure is not ready for this, it is simpler to use a monolith.
• Performance and latency: inter-service communication over the network adds delays. In a monolith, function calls are faster.
• Transactional requirements: if complex data consistency is needed, it is easier to implement it in a monolith.
• Initial project stage: it is easier to start with a monolith and then, if necessary, split into microservices.

Thus, transitioning to a monolith is justified when the advantages of microservices do not outweigh the costs of their support and complexity.