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LetsGit.IT/Categories/Monoliths
Monolithsmedium

How to keep a monolith maintainable as it grows?

Tags
#modular-monolith#boundaries#maintainability
Back to categoryPractice quiz

Answer

Keep clear module boundaries (often by domain), enforce dependency rules, keep layers thin, and add automated tests. Prefer internal APIs, limit shared state, and refactor regularly so the monolith stays modular and changeable.

Advanced answer

Deep dive

Expanding on the short answer — what usually matters in practice:

  • Context (tags): modular-monolith, boundaries, maintainability
  • Scaling: what scales horizontally vs vertically, where bottlenecks appear.
  • Reliability: retries/circuit breakers/idempotency, observability (logs/metrics/traces).
  • Evolution: keep changes cheap (boundaries, contracts, tests).
  • Explain the "why", not just the "what" (intuition + consequences).
  • Trade-offs: what you gain/lose (time, memory, complexity, risk).
  • Edge cases: empty inputs, large inputs, invalid inputs, concurrency.

Examples

A tiny example (an explanation template):

// Example: discuss trade-offs for "how-to-keep-a-monolith-maintainable-as-it-grows?"
function explain() {
  // Start from the core idea:
  // Introduce clear module boundaries (by domain), enforce dependency rules, keep layers thin,
}

Common pitfalls

  • Too generic: no concrete trade-offs or examples.
  • Mixing average-case and worst-case (e.g., complexity).
  • Ignoring constraints: memory, concurrency, network/disk costs.

Interview follow-ups

  • When would you choose an alternative and why?
  • What production issues show up and how do you diagnose them?
  • How would you test edge cases?

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