intermediate

HTTP-Only Mode (Without WebSocket)

Run djust without WebSockets: HTTP polling for environments where WS is blocked.

On this page

djust can run without WebSockets. With use_websocket: False, the client uses the SSE transport: the server pushes updates over an EventSource stream, and the client sends events as HTTP POST requests. Only in a browser without EventSource does it fall back to POSTing events to the page URL. This is useful for:

Testing without WebSocket infrastructure
Environments where WebSocket connections are blocked
Simpler deployment scenarios
Debugging and development

Configuration

Option 1: Django Settings (Global)

Add to your settings.py:

LIVEVIEW_CONFIG = {
    'use_websocket': False,  # Disable WebSocket, use HTTP-only mode
}

Option 2: Programmatic Configuration

from djust.config import config

# Disable WebSocket
config.set('use_websocket', False)

Mount the SSE endpoint

The SSE transport needs its URL patterns. Add them to your root URLconf:

from django.urls import include, path
from djust.sse import sse_urlpatterns

urlpatterns = [
    # ...
    path("djust/", include(sse_urlpatterns)),
]

Without these routes the stream at /djust/sse/<session>/ returns 404, the client marks the transport disabled and fires dj-disconnected, and events do nothing.

How It Works

With WebSocket (Default)

Browser                    Server
   |---WebSocket Connect--->|
   |<--Connected------------|
   |---Event: click-------->|
   |<--Patches--------------|
   |---Event: change------->|
   |<--Patches--------------|

With `use_websocket: False` (SSE transport)

Browser                                   Server
   |---GET /djust/sse/<session>/ (EventSource)-->|
   |<==stream: patches ==========================|
   |---POST /djust/sse/<session>/message/ ------>| (event + params)
   |<==stream: patches ==========================|

Fallback: browsers without `EventSource`

Browser                    Server
   |---POST <page URL> ---->| (event + params)
   |<--JSON patches---------|

Behavior Differences

Feature	WebSocket Mode	SSE / HTTP Mode
Connection	Persistent	SSE stream + one POST per event
Latency	Lower (~10ms)	Higher (~50-100ms)
Server Load	Lower	Higher (new request per event)
Fallback	To SSE, if mounted	To page POST, if no `EventSource`
Deployment	Requires WebSocket support	Standard HTTP only

Example: HTTP-Only LiveView

# views.py
from djust import LiveView
from djust.decorators import event_handler

class CounterView(LiveView):
    template_name = 'counter.html'

    def mount(self, request, **kwargs):
        self.count = 0

    @event_handler
    def increment(self, **kwargs):
        self.count += 1

    @event_handler
    def decrement(self, **kwargs):
        self.count -= 1

<!-- counter.html -->
<!DOCTYPE html>
<html>
<head>
    <title>Counter (HTTP Mode)</title>
</head>
<body>
    <div dj-root>
        <h1>Counter: {{ count }}</h1>
        <button dj-click="increment">+</button>
        <button dj-click="decrement">-</button>
    </div>
</body>
</html>

Testing HTTP Mode

Set the configuration:

# settings.py
LIVEVIEW_CONFIG = {
    'use_websocket': False,
}

Run the server:
```
python manage.py runserver
```
Check browser console (with DEBUG=True and globalThis.djustDebug = true):
- Should see: [LiveView] WebSocket disabled, using SSE transport directly
- In a browser without EventSource: [LiveView] HTTP-only mode (use_websocket: false)
- No WebSocket connection attempts
Test interactions:
- Click events trigger HTTP POST requests to /djust/sse/<session>/message/
- Check the Network tab in DevTools: one open EventSource stream, plus one POST per event

Performance Considerations

WebSocket Mode (Recommended for Production)

✅ Lower latency
✅ Persistent connection
✅ Better for frequent updates
✅ Lower server load

HTTP Mode (Good for Development/Testing)

✅ Simpler infrastructure
✅ No WebSocket configuration needed
✅ Easier debugging (see requests in Network tab)
⚠️ Higher latency
⚠️ More server load

Automatic Fallback

If the WebSocket exhausts its reconnect attempts and the SSE endpoint is mounted (include(sse_urlpatterns)), djust switches to the SSE transport automatically. Without SSE mounted there is no automatic fallback.

Troubleshooting

Events not working in HTTP mode

Check:

sse_urlpatterns is mounted (see Mount the SSE endpoint); the stream at /djust/sse/<session>/ must not 404
Event handlers are decorated with @event_handler (the default event_security = "strict" rejects undecorated methods)
Browser console for errors
Django middleware allows POST requests

WebSocket won't disable

Verify:

Configuration is loaded: from djust.config import config; print(config.get('use_websocket'))
Clear browser cache
Hard reload the page (Cmd+Shift+R / Ctrl+Shift+R)