Agent X Alpha

WebSocket & Server-Sent Events (SSE) Live Tester

Client-SideOffline Ready

Inspect, test, and debug real-time WebSockets (ws://, wss://) and Server-Sent Events (SSE) streams live in your browser with automated JSON formatting, heartbeats, and zero server uploads.

Sample Endpoints:
disconnected—Ready to connect
Uptime:00:00
0 B
0 B

Send Message

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Cmd/Ctrl + Enter to send
97 bytes
Pro Tip: Connect to wss://stream.binance.com:9443/ws/btcusdt@trade to test high-frequency streaming data, or use Postman Echo to test your send/receive request flow.

Live Stream Feed

0 msgs

No messages in stream

Click "Connect" above to start streaming events.

WebSocket vs Server-Sent Events (SSE) Quick Reference

FeatureWebSocket (RFC 6455)Server-Sent Events (SSE)
DirectionalityBi-directional (Full duplex, client ↔ server)Uni-directional (Server → client only)
Underlying ProtocolTCP Socket (via HTTP Upgrade handshake)Standard HTTP / HTTP/2 / HTTP/3
ReconnectionMust be handled manually in client codeBuilt-in automatic reconnection by browser
Message PayloadsUTF-8 Text and Binary (ArrayBuffer / Blob)UTF-8 Text only (e.g. JSON strings)
Best ForChat apps, online gaming, collaborative whiteboardsLLM token streams, live news, notifications, dashboards

Zero-Proxy Direct Connection

Connections execute directly from your browser to the destination endpoint using native WebSocket and EventSource APIs. No packets are proxied or captured by our servers.

Dual Protocol Inspection

Test full-duplex bi-directional WebSockets (ws:// and wss://) and uni-directional Server-Sent Events (SSE) side-by-side with automatic JSON formatting and event filtering.

Live Metrics & Heartbeats

Track connection uptime, message throughput, packet payload sizes, and configure automated ping heartbeats to monitor real-time round-trip latency (RTT).

Frequently Asked Questions

What is the main difference between WebSockets and Server-Sent Events (SSE)?
WebSockets provide full-duplex, bi-directional communication over a persistent TCP connection where both the client and server can send messages at any time. Server-Sent Events (SSE) are uni-directional (server-to-client only) running over standard HTTP/1.1 or HTTP/2, featuring built-in reconnection, event IDs, and native text streaming.
Why can I not set custom HTTP headers on WebSocket connections in the browser?
The browser-native WebSocket API does not allow setting custom HTTP request headers (like Authorization or Cookie) during the initial HTTP upgrade handshake due to browser security and CORS restrictions. Instead, authentication is typically handled via query parameters (e.g. ?token=...) or an initial authentication message sent immediately after connecting.
How do Server-Sent Events (SSE) handle reconnections automatically?
The EventSource browser standard automatically reconnects if the connection drops. If the server sends an "id: <number>" field with messages, the browser automatically sends a "Last-Event-ID" HTTP header upon reconnecting, allowing the server to resume missed events seamlessly.
Is my data private when testing through this tool?
Yes, 100% private. All WebSocket and EventSource connections originate directly from your browser client to the destination server. AgentXAlpha does not proxy, intercept, log, or store your message payloads.
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