モノリスとマイクロサービス

Two ways to structure software: the monolith and microservices. Knowing both helps you pick wisely as your SaaS grows.

A monolith bundles UI, business logic, and data access into one tightly-coupled app, deployed as a single unit. One big building, all departments inside.

A monolith is simpler to build, test, and deploy early, easy to debug in one codebase, and fast thanks to in-process calls. Great for an MVP.

As a monolith grows it bites back: you scale the whole app at once, changes get risky, tech is locked in, and one bug can take everything down.

Microservices split your app into small, independent services, each owning one capability and talking over APIs. Think a mall of specialized shops.

Microservices let you scale only what is hot, mix technologies per service, deploy one piece without touching the rest, and isolate failures.

Microservices add real cost: more moving parts to operate, distributed-system headaches like latency and consistency, and trickier cross-service debugging.

Early-stage SaaS? A monolith ships faster, suits small teams, and keeps infra costs low. You can always split it out later as you scale.

As your SaaS scales, microservices start to pay off: scale hot services, let teams ship independently, stay resilient, and adopt new tech piecemeal.

Which of the following is a primary advantage of a microservices architecture over a monolithic one for a growing SaaS application?

Recap: monoliths are simpler but harder to scale; microservices are complex but scale and evolve far better. Many start mono, split later.