Design decisions go a long way in impacting the scalability of a single microservice. As with other application capabilities, decisions that are made during the design and early coding phases largely influence the scalability of services.
Microservice scalability requires a balanced approach between services and their supporting infrastructures. Services and their infrastructures also need to scale in harmony.
Scalability is one of the important non-functional characteristics of a system by which it can handle more payload. It is often felt that scalability is usually a concern for large-scale distributed systems. Performance and scalability are two different characteristics of a system. Performance deals with the throughput of the system, whereas scalability deals with serving the desired throughput for a larger number of users or a larger number of transactions.