RACI Matrix
Who is responsible, accountable, consulted and informed for each architectural decision type — with exactly one accountable per row.
Decision types down the side, roles across the top. The rule that gives it force is exactly one A per row. Two accountable parties means the decision stalls; none means it is made by whoever moves first.
The shape
| Decision | Solution Architect | Enterprise Architect | Eng Lead | Security | Product | CTO |
|---|---|---|---|---|---|---|
| Service decomposition | A | C | R | I | C | I |
| Technology selection, within radar | A | C | R | C | I | I |
| Technology selection, off radar | R | A | C | C | I | C |
| Data model, own domain | C | I | A/R | I | C | I |
| Data shared across domains | R | A | C | C | I | I |
| Public API contract | A | C | R | C | C | I |
| Authentication approach | C | C | R | A | I | I |
| Cloud region and residency | R | C | I | C | I | A |
| Non-functional targets | R | I | C | C | A | I |
| Accepting a security exception | I | C | R | R | C | A |
| Third-party dependency | R | C | R | C | A | I |
| Deprecating a platform API | C | A | R | I | C | I |
When you produce it
At the start of a programme with more than one team, and immediately after any argument that turned out to be about who decides rather than about the decision. Also when a new architecture function is being set up and needs to state what it will and will not decide.
Who reads it
Everyone named in it, which is the point. Programme leadership, when something is stuck. New joiners in an architecture role, as the fastest description of the job.
What good looks like
- Exactly one A per row. Enforce it; it is the whole mechanism.
- Rows are decision types, not tasks. "Attend the design review" is not a decision.
- R and A are distinguished properly: the accountable role answers for the outcome, the responsible role does the work. They are often different people and the matrix should not blur them.
- C is short. Consulting eight roles means consulting none of them properly.
- It names the escalation path when the A is unavailable or disagrees.
Common mistakes
- Two accountable roles, which is how a decision takes six weeks.
- Everyone consulted on everything, which turns into a standing meeting.
- Written and filed. It only works if it is cited the first time somebody reaches past it.
- Confusing it with an org chart. Accountability for a decision is not the same as line management.