The Postmark team experienced a series of outages caused by a failure in their MongoDB cluster, leading to delayed emails, disabled activity, and a down Bounce API. The issue was exacerbated by the high volume of data captured daily, which required constant purging and compaction to maintain performance. However, this process put additional load on the servers, causing inconsistencies in email sending services and activity statuses. On the positive side, the outages led to an improved Bounce API with near-instant responses, thanks to a rebuild that now uses Elastic Search directly. The team is reevaluating their architecture, planning thorough benchmarking of other databases to ensure seamless real-time sending without compromising the email archive.