Monoliths and Microservices

Why This Decision Appears

A founder is reviewing how the product will enforce rules and respond when a request does not go to plan.

The immediate question is monoliths and microservices. The technical label matters only because it changes a product decision, a responsibility, or the evidence required before launch.

The Working Principles

Start with the product consequence, then choose the simplest technical treatment that protects it. A longer tool list is not a stronger plan.

For this decision, the useful standard is that important rules hold for valid, invalid, repeated, and unauthorised requests.

• Make the decision explicit: Prefer a well-structured monolith until independent scaling, ownership, or release needs justify distributed operations.
• Ask what evidence would show that the chosen approach works.
• Name the person or provider responsible when the approach fails.
• Record the result in the backend proposal and operational acceptance criteria.

How to Choose Without Overbuilding

Prefer a well-structured monolith until independent scaling, ownership, or release needs justify distributed operations.

The principal risk is that service boundaries multiply deployment and failure complexity before the organisation can support them. This does not require the most expensive possible solution. It requires the consequence to be understood and the control to match it.

1. Describe the user or business outcome that must be protected.
2. Identify the most credible failure and its consequence.
3. Compare the simplest adequate approach with one realistic alternative.
4. Set a review point for when the decision may need to change.

A Useful Proposal and an Impressive-sounding One

Warning Signs

• Nobody can explain how monoliths and microservices changes a user or business outcome.
• The proposal does not address this risk: service boundaries multiply deployment and failure complexity before the organisation can support them.
• The only evidence is a successful demonstration of the easiest path.
• The decision has no named owner, boundary, or review point.
• A provider-specific feature is being mistaken for a permanent product requirement.

Questions to Ask a Consultant

• What decision are we making about monoliths and microservices?
• Which user or business outcome does the recommendation protect?
• How have we reduced or accepted this risk: service boundaries multiply deployment and failure complexity before the organisation can support them.
• What evidence can I review without relying on the original implementer?
• What is deliberately deferred, and when will it be reconsidered?
• Who owns the accounts, data, documentation, and recovery process?