Monolith vs microservices
In a monolith, one application stack (interface, logic, data) runs together. You harden a smaller number of boundaries — TLS, headers, patching, and depth at the perimeter — but a serious flaw can have wide blast radius across the whole app.
In microservices, capability is split into smaller services that talk over the network. Each path needs consistent authentication, authorization, least-privilege access to data, and protected service-to-service traffic (for example mutual TLS or signed internal requests).




