Events Glossary

A collection of terms related to events, event-driven architecture, and associated patterns

Terminology in the field of event-driven architecture can be confusing. It's not standardized. Or as Wikipedia puts it: "There are different types of events in EDA, and opinions on their classification may vary."[1]

This glossary reflects my understanding of what the author who coined or used the term described (and I'll link to the source of the definition so you can check for yourself). I think it can be useful (if nothing else, for me to remember what all the terms mean), but I can't guarantee correctness. Other authors, vendors, and communities might use the terms differently. If you have suggestions for improvements, please let me know.

C

Clickbait Event
An alternative term for "Event Notification", emphasizing the idea that the event is designed to attract attention and prompt the receiver to take action (i.e., click through to get more information), rather than providing sufficient data for the receiver to update its state independently. [3]

D

Domain Event
An event that describes something interesting that occurred in a business domain. Domain events use the ubiquitous language of the domain and are meaningful to business stakeholders. "OrderPlaced", "PaymentReceived", "AuctionClosed" are examples. In some literature, domain events are distinguished from integration events by their scope of visibility. [1]

E

Event-Carried State Transfer
A term from Martin Fowler's taxonomy describing events that carry enough data for consumers to update their local state without querying the source. It is often understood to mean a "fat event" that includes a complete snapshot of the entity's state. But in the original article, the wording is "details of the data that changed". So it could also be interpreted as a "delta event" that only includes the changed fields, as long as they are sufficient for consumers to update their state without additional lookups. [2]
Event Notification
An event that doesn't carry actual data, only some id and a link back to the sender that can be queried for more information. The receiver knows something has changed, but then makes a request back to the sender get the actual data. See Clickbait Event. [2]

I

Integration Event
An event that is published across service boundaries for other services to consume. The term is used in Domain-Driven Design literature to distinguish events shared externally from domain events that may be processed only within a bounded context. In practice, when we talk about events in event-driven architecture, we typically mean integration events. [1]

Sources

  1. Wikipedia: Event-driven architecture
  2. Martin Fowler (2017): What do you mean by “Event-Driven”?
  3. Oskar Dudycz (2025): Event-driven Modeling Anti-Patterns

← Back to Resources