Choosing the Right Modernization Path: Developing a Decision Framework for Modular Monoliths and Microservices in Enterprise Applications

Abstract

Enterprise application modernization is frequently framed as a monolith-to-microservices migration even when modularization, selective extraction, or retention may provide a better fit. This study develops and qualitatively refines the Enterprise Modernization Path Decision Framework (EMPDF) for choosing among retaining and improving a monolith, adopting a modular monolith, selectively extracting services, and pursuing broader microservices migration. A literature synthesis was combined with three semi-structured expert interviews using the same five non-leading questions. Each transcript was analyzed independently using hybrid deductive-inductive thematic analysis before cross-expert synthesis and comparison with the literature-derived framework. Five themes were identified: business value and system criticality as the entry gate; boundary and data feasibility; engineering and organizational readiness; distributed-system risk and business-continuity exposure; and incremental, measurable, reversible modernization. Expert evidence broadly converged with the literature while extending it through stronger attention to application rationalization, domain-knowledge retention, security and governance, business-as-usual continuity, rollback mechanisms, and outcome measurement. The refined EMPDF retains eight dimensions but introduces a value-and-rationalization gate, staged readiness checks, and an explicit reassessment loop. The contribution is an evidence-traceable framework that treats architecture distribution as conditional rather than inherently progressive. Findings are exploratory and expert-informed; three purposively selected interviews do not establish generalizability, saturation, predictive validity, or proven effectiveness.