Microservices vs Monolith: Decision Framework for 2025

Architecture is a product of org realities. This guide provides a decision framework grounded in domain complexity, team size, deployment frequency, and operational maturity.

Decision factors

• Domain coupling and change cadence
• Team topology and ownership
• Operational maturity (observability, CI/CD, SRE)
• Performance and data boundaries

Matrices and scenarios

• Small team, fast iteration → modular monolith
• Large org, bounded contexts, independent lifecycles → microservices

Migration paths

• Strangler fig pattern; extract by bounded context; shared kernel reduction

Ops considerations

• Platform engineering, golden paths, templates
• Observability and SLOs per service; cost monitoring

Appendix A — Checklist

• Ownership, contracts, deployment, observability, resilience, security

Appendix B — Top‑Up Index (1–200)

1. Checklist item 001
2. Checklist item 002
3. Checklist item 003
4. Checklist item 004
5. Checklist item 005