Solving E2E Test Flakiness with Per-Test Email Isolation

Shared email inboxes are a leading cause of test flakiness in E2E suites, causing false passes and wasted debugging time when concurrent test workers collide over a single inbox. Ephemeral inboxes—where each test gets its own temporary email address under a wildcard domain—eliminate race conditions at the infrastructure level, making tests truly isolated and reliable. This approach trades DNS complexity for operational simplicity, allowing developers to spawn unlimited test addresses without per-address provisioning costs.