A stateless topic has no state. It can be used for publishing and receiving updates, but not for fetching the current topic state.

Stateless topics are the only type of topic provided in other typical pub-sub solutions.

Why use a stateless topic?

You can use stateless topics for data streams where there is no current state of the data, only updates. For example, a feed of news items.

All handling of the topic and topic data of a stateless topic is done by your client application. Because of this, the format of the data published on a stateless topic is entirely flexible. The topic content is treated as byte data by the Diffusion server. How that byte data is handled and interpreted is determined by your client applications.

Considerations when using a stateless topic

A stateless topic does not store state. You cannot fetch the topic state and when you first subscribe to a stateless topic you do not receive the topic state as a value as you do with a stateful topic.

You must write all of the logic in your client to handle the byte data that is published on a stateless topic. This might mean it takes longer to get started using a stateless topic compared to topics that are handled by the Diffusion server.

You also lose some of the benefits of having a topic whose content is understood by the Diffusion server, such as validation, formatting, conflation, and deltas.