What is replacing WebSockets?
Nothing is replacing WebSockets outright. RFC 6455 is still the only full-duplex transport every browser supports, and it is not deprecated. What has changed is that two jobs people used to hand to WebSockets moved elsewhere: one-way streaming went to Server-Sent Events, and low-latency or lossy traffic is moving to WebTransport over HTTP/3.
Why the question keeps coming up
For about a decade, "the server needs to push something" meant opening a WebSocket, because it was the only option that worked everywhere. That default is what eroded, not the protocol.
Two things pushed the change. Streaming AI responses made SSE visible to a very large number of developers at once: ChatGPT streams tokens over SSE, not WebSockets, and once one high-profile product showed that a plain HTTP response was enough, plenty of teams reexamined their own use of a socket. At the same time HTTP/3 shipped, and with it WebTransport, which is genuinely new capability rather than a repackaging of what already existed.
Server-sent events took the one-way cases
Most real-time features were never bidirectional. A notification feed, a progress bar, a live dashboard, a log tail, and a streaming model response all move data in one direction, from server to client. The client's occasional input goes back over a normal POST and does not need the same connection.
Server-sent events do exactly that job over ordinary HTTP. The response has a Content-Type of text/event-stream and stays open while the server writes data: lines to it. Because it is a regular HTTP response, it passes through proxies, CDNs, and corporate firewalls that need explicit configuration to allow WebSocket upgrades, and the browser's EventSource reconnects on its own and replays from the last event ID. There is less to build and less to operate. WebSocket vs SSE covers the full comparison.
The catch is the HTTP/1.1 six-connections-per-origin limit, which counts held-open SSE streams the same way it counts long polls. Over HTTP/2 that ceiling disappears.
WebTransport is the closest thing to a successor
WebTransport is the one technology that could reasonably be described as a next-generation WebSocket. It runs over HTTP/3 and QUIC, and it offers what WebSockets structurally cannot: multiple independent streams over one connection with no head-of-line blocking between them, plus unreliable datagrams for data where a dropped packet is better than a late one.
That matters for cloud gaming, live media, and anything where a single stalled message currently blocks everything queued behind it on a WebSocket's single ordered channel. It shipped in Chromium browsers first, with other engines following, so a production deployment usually still needs a WebSocket fallback path. Treat it as an addition to the toolbox rather than a migration you owe anyone.
What was never WebSocket territory
A large share of "we need real-time" turns out to be server-to-server, and neither WebSockets nor WebTransport is a good fit there. Holding a socket open between two backends means paying for a connection that sits idle almost all the time, plus reconnection logic, plus your own delivery guarantees, and it gives you nothing you can replay when the receiving service was down during a deploy.
Webhooks invert that: one short HTTP request per event, only when there is an event, with retries and signatures handled at the message level instead of the connection level. That model has been growing while WebSocket usage between backends has been shrinking, which is another reason the "what is replacing WebSockets" question gets asked. Webhook vs WebSocket works through where the line falls, and Svix provides the sending side, including retries and signature verification, for teams that do not want to build it.
Choosing a transport today
Start from the direction of traffic. If data only flows server to client and the client is a browser, use SSE. If both sides send messages during the same session, such as chat, collaborative editing, or multiplayer state, use a WebSocket, and expect it to stay the right answer for years. If you need unordered or unreliable delivery and can carry a fallback, evaluate WebTransport. If both ends are servers, use webhooks or a message queue instead of any persistent socket.
The one migration actually worth doing is the first case: a WebSocket carrying strictly one-way traffic is complexity you can delete.
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Svix handles signing, retries, rate limiting, and delivery observability for the webhooks you send to your users, so your team can stay focused on your product.
Start sending webhooks with Svix or read the build vs. buy analysis