What is a "streaming app", exactly?

I'm trying to get past all the hipster, pie-in-the-sky buzzwording and address a very simple, fundamental question: What is a streaming application? According to the Kafka site "Kafka is used for building real-time data pipelines and streaming apps" Streaming apps...hmmm. OK, so what is a "streaming app"?! According to Quora, a Java stream is: [A sequence] of bytes that you can read from (InputStream and its subclasses) or write to (OutputStream and its subclasses)... Doesn't seem like that definition fits. From what I can gather from various articles, a "streaming app" appears just be an app that is constantly being fed data. But doesn't that definition also apply to: A RESTful HTTP service, whose web clients are constantly sending it data all day long (and also, querying it for data) A standard message broker (AMQP, etc) whose clients are constantly reading/writing to its queues all day long Any TCP-based network server, whose TCP clients are constantly reading/writing data to it all day long (including MMO game servers) ?!?! So I ask, because someone, somewhere really needs to bring clarity to this: "Is a streaming app just trendy, hipster buzzword banter, or is there a distinctive definition for a streaming app that sets it apart from all my examples above?"

Jun 23, 2025 - 21:30

I'm trying to get past all the hipster, pie-in-the-sky buzzwording and address a very simple, fundamental question:

What is a streaming application?

According to the Kafka site

"Kafka is used for building real-time data pipelines and streaming apps"

Streaming apps...hmmm. OK, so what is a "streaming app"?! According to Quora, a Java stream is:

[A sequence] of bytes that you can read from (InputStream and its subclasses) or write to (OutputStream and its subclasses)...

Doesn't seem like that definition fits. From what I can gather from various articles, a "streaming app" appears just be an app that is constantly being fed data. But doesn't that definition also apply to:

A RESTful HTTP service, whose web clients are constantly sending it data all day long (and also, querying it for data)
A standard message broker (AMQP, etc) whose clients are constantly reading/writing to its queues all day long
Any TCP-based network server, whose TCP clients are constantly reading/writing data to it all day long (including MMO game servers)
?!?!

So I ask, because someone, somewhere really needs to bring clarity to this: "Is a streaming app just trendy, hipster buzzword banter, or is there a distinctive definition for a streaming app that sets it apart from all my examples above?"