Do You Really Need WebSockets for Streaming Data

I was chatting with a colleague about streaming data to the client. The topic came up casually, and it got me curious enough to look into how this is typically handled in modern systems.

The question was simple:

If you only need one-way streaming, should you still use WebSockets?

Why this idea exists

Historically, HTTP wasn't great at streaming. Early versions like HTTP/1.1 chunked transfer encoding support allowed chunked responses, but in practice the experience was inconsistent. Proxies often buffered responses, browser support was uneven, and there wasn't a clean abstraction for "live" data delivery.

Because of this, systems gradually moved toward long polling and later WebSockets when they became widely adopted. That led to a simple mental model:

HTTP is request/response, WebSocket is streaming

It's a neat simplification, but it doesn't reflect how things work today.

What changed in practice

Over time, HTTP streaming became much more practical. HTTP/2 multiplexing improved connection efficiency and made long-lived responses feel more natural. On the browser side, fetch() with ReadableStream made incremental consumption a standard pattern rather than a workaround.

A key example of this shift is Server-Sent Events (SSE), a unidirectional event streaming approach over HTTP, which provides a simple way to stream data from server to client over a single HTTP connection. The server keeps the connection open and pushes events as they happen, while the browser handles parsing, reconnects, and delivery automatically. It is intentionally one-way, which keeps it simple and practical for notifications, logs, and incremental updates.

Infrastructure also improved. CDNs, proxies, and load balancers became more reliable at handling streamed responses without forcing buffering. As a result, HTTP-based streaming became a first-class option instead of something fragile.

The real tradeoff

The decision isn't really "streaming vs WebSocket", but one-way vs two-way communication and the complexity you're willing to take on.

For one-way flows like LLM streaming, logs, progress updates, or incremental API responses, HTTP streaming (including SSE) is usually enough and simpler to operate. It fits existing infrastructure, avoids persistent connection management, and keeps systems stateless.

WebSockets make sense when you need true bidirectional, low-latency communication, such as chat, collaboration, or multiplayer systems. Outside of that, they mainly add operational complexity without much benefit.

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