SSE Tester
Free online SSE tester, no installation required. Test Server-Sent Events connections and view real-time messages
What is Server-Sent Events (SSE)?
Server-Sent Events (SSE) is a server push technology enabling a browser to receive automatic updates from a server over HTTP connection. Unlike WebSockets which are bidirectional, SSE is one-way (server to client). It's perfect for live updates, notifications, stock tickers, and real-time feeds.
How to Use This SSE Tester
Enter an SSE endpoint URL, click Connect to subscribe. The tool displays incoming events with their data, event type, and ID. You can monitor connection status and view all received messages in real time.
▶What's the difference between SSE and WebSockets?
SSE is one-way (server to client) over HTTP, simpler to implement, automatically reconnects, and supports text only. WebSockets are bidirectional, support binary data, but require more setup. Use SSE for one-way data streams like notifications.
▶Does SSE work in all browsers?
SSE is supported by all modern browsers. Internet Explorer does not support SSE, but polyfills are available. Edge, Chrome, Firefox, and Safari all have native support.
▶Can I send headers or authentication?
This tool opens a basic GET connection to the SSE endpoint. For authenticated endpoints, the URL may need to include tokens or query parameters.
If this tool helped you, consider buying the author a coffee.
Buy Me a Coffee