What is the difference between a postmortem and an RCA?
A postmortem is a review process, usually a meeting and a write-up, that reconstructs an incident to learn from it; a root cause analysis is the specific determination of why the incident happened, supported by evidence. Postmortems, particularly blameless ones from the SRE tradition, focus on timeline, human factors and systemic lessons, and they may deliberately avoid naming a single cause. An RCA is narrower and more formal: it states the trigger, propagation and failure, separates contributing factors from the root cause, and drives corrective actions. Customers, auditors and problem-review boards ask for an RCA. Engineering teams run postmortems. A good incident process produces both.
Onepane delivers the RCA and the evidence behind it, so your postmortem meeting starts from an established cause instead of reconstructing one.