Comparison: Monolith vs Microservices vs Modulith
Comparative table of the three main architectural styles.
#Executive Summary
| Axis | Monolith | Modulith | Microservices |
|---|---|---|---|
| Deployment Units | 1 | 1 | N |
| Databases | 1 | 1 (with separate schemas) | N per service |
| Internal Communication | Method call | In-process call/event | Network (HTTP/MQ) |
| ACID Transactions | Yes | Yes | No (Saga) |
| Operations | Minimal | Low | High |
| Granular Scaling | No | No | Yes |
| Ideal Team Size | 1-15 | 5-30 | 30+ |
| Cost of Getting it Wrong | Low (refactor) | Low (refactor) | High (rewrite) |
| Time to First Deploy | Days | Days | Weeks |
#Which one should I choose?
CSHARP
Team < 15 people? → Monolith or Modulith
Multiple clear bounded contexts? → Modulith
Need to scale parts 10×+? → Microservices (partial)
Have a platform team? → Microservices viable
Product seeking PMF? → Always Monolith#Key questions before deciding
| Question | If the answer is… | Lean towards |
|---|---|---|
| How many people write code? | Fewer than 15 | Monolith / Modulith |
| How many independent teams are there? | Many, blocking each other on deploy | Microservices |
| What is the infra and platform budget? | Limited | Modulith |
| Do you have a measured bottleneck? | One component must scale separately | Extract only that component |
| Is the bottleneck tangled code? | Yes | Modulith (a logical problem, not a physical one) |
| Is the domain clear and stable? | No, you are still discovering it | Monolith: wrong boundaries are expensive |
| Do you need consistent transactions across parts? | Yes | Modulith / Monolith |
| Is observability and CI/CD mature? | No | Don't use microservices yet |
| Isolation requirements (compliance, failures)? | Strict | Separate service for that part |
Microservices is an organization and scale decision, not a technical quality one. If you can't justify it with teams, measured load or regulatory isolation, a Modulith is enough.
Rule: start monolithic, modularize from day 1, extract microservices only when the pain justifies it.
Visual Summary
| Style | Main Pro | Main Con |
|---|---|---|
| Monolith | Total simplicity | Couples teams and scaling |
| Modulith | Best cost/benefit ratio | Requires discipline |
| Microservices | Autonomy and scaling | Very expensive operations |
#comparison