Priority isolation.

also: priority queues · priority queue · priority lanes

Separate queues and workers per priority, so a bulk campaign can never delay critical notifications such as OTPs or security alerts.

the two-minute refresher

Classify first: security (critical), transactions (high), reminders and social (medium), marketing (low).
A 10M-notification campaign shares nothing with the critical path: own topics, workers and provider quota.
The same idea as bulkheads, applied to message priority.

also: priority queues · priority queue · priority lanes

Separate queues and workers per priority, so a bulk campaign can never delay critical notifications such as OTPs or security alerts.

Classify first: security (critical), transactions (high), reminders and social (medium), marketing (low).
A 10M-notification campaign shares nothing with the critical path: own topics, workers and provider quota.
The same idea as bulkheads, applied to message priority.