NestJS · Senior · Question 17 of 75

How do you get reliable event publishing from a Nest service that also writes to the database?

1Call client.emit() before committing
2Call client.emit() after committing and hope it succeeds
✓Correct answer: Use a transactional outbox: write the event row in the same transaction, and a separate publisher sends it to the broker

Explanation

Emitting outside the transaction can lose or duplicate events if either step fails.

Further reading

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