Event types (domain, integration, notification) in Microservices - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a domain event in microservices?

A domain event represents something important that happened inside a service's business logic. It reflects a state change or action relevant to the service's core domain, like 'OrderPlaced' or 'PaymentProcessed'.

beginner

Define an integration event and its purpose.

An integration event is used to communicate between different microservices. It shares information about changes so other services can react or update themselves, ensuring loose coupling and eventual consistency.

beginner

What is a notification event and when is it used?

A notification event informs users or external systems about something that happened, like sending an email or SMS. It is often used for alerts, confirmations, or updates outside the core business logic.

intermediate

How do domain events differ from integration events?

Domain events focus on internal business changes within a service, while integration events are designed to share those changes with other services to coordinate actions across the system.

intermediate

Why is it important to separate notification events from domain and integration events?

Separating notification events keeps user communication or external alerts independent from core business logic and service coordination, making the system easier to maintain and scale.

Which event type represents a change inside a single microservice's business logic?

A System event

B Integration event

C Notification event

D Domain event

Domain events capture important changes within a service's own domain.

What is the main purpose of an integration event?

A To communicate changes between microservices

B To log internal errors

C To notify users about system status

D To trigger UI updates

Integration events share information between services to keep them in sync.

Which event type would you use to send an email confirmation after an order is placed?

A Domain event

B Integration event

C Notification event

D Audit event

Notification events handle user or external system alerts like emails.

Which statement is true about domain and integration events?

A Domain events represent internal changes; integration events share those changes externally

B Integration events are internal to a service

C Domain events are for external communication only

D Both are the same and interchangeable

Domain events are internal; integration events share changes across services.

Why keep notification events separate from domain events?

A Because notification events are faster

B To avoid mixing business logic with user communication

C Notification events are only for debugging

D They are stored in different databases

Separating them keeps the system clean and easier to maintain.

Explain the differences between domain, integration, and notification events in microservices.

Think about where the event happens and who needs to know about it.

Describe a real-life example scenario using all three event types in a microservices system.

Consider an online shopping system with order processing and user notifications.