Describe the problem and constraints
State the decision being made and the conditions that matter. Include workload expectations, operational skills, existing systems, and requirements that rule out otherwise plausible options.
Distinguish observed constraints from assumptions. If the choice depends on a volume estimate or a supplier capability that has not been verified, say so. Future readers need to know which parts of the reasoning can be invalidated by new evidence.
Record the alternatives fairly
Describe the options seriously considered and why each did or did not fit. Avoid presenting the chosen approach as the only reasonable possibility after the decision has already been made.
Capture the consequences of the choice, including work it creates. Introducing a separate service may help one boundary while adding deployment and monitoring responsibilities. Keeping a component together may simplify operation while limiting how independently it can change.
Define a reason to revisit it
Name the conditions that would justify reconsideration. That might be a different workload, a new operational requirement, or an assumption proving false. This keeps the record useful without making every earlier decision an obstacle to change.
Keep the document short, dated, and linked to the relevant code or issue. When a later decision supersedes it, preserve the earlier reasoning and connect the two records.
The purpose is not to document every minor preference. It is to retain the reasoning behind choices that would otherwise be difficult to reconstruct, so future maintainers can distinguish a deliberate tradeoff from an accidental arrangement that nobody remembers choosing.
A practical example.
Suppose a team chooses a scheduled import instead of a live integration. The decision record should explain the required freshness, the source system’s limitations, and the operational cost of the alternatives. “Simpler” is useful only when readers know what complexity was avoided.
Record the consequences as well: updates may arrive later, reconciliation is necessary, and the import needs an owner. Add the conditions that would justify revisiting the choice, such as a changed business requirement for freshness. Keep the original record when a later decision replaces it. That history helps a future maintainer distinguish a deliberate tradeoff from an accidental limitation and prevents the team from repeatedly investigating the same options without new evidence.
Put it into practice.
- Describe the context, alternatives, and reason for the selected option.
- Include operational consequences and assumptions that could change.
- Link replacement decisions instead of silently rewriting the original rationale.