Server-Sent Events Tester
Connect to any SSE endpoint URL and inspect events live in your browser. Track standard and custom event names, monitor connection status, and export stream logs for debugging and QA.
Endpoint must support text/event-stream responses.
Range: 20 to 2000
Status
Idle
Events
0
Errors
0
Why Use This SSE Tester?
A practical EventSource testing surface for endpoint validation and debugging workflows.
Real-time event visibility
Watch events as they arrive and inspect payloads without opening DevTools network frame parsers each time.
Custom event listener support
Register listeners for named SSE events and verify exactly which event channels your backend emits.
Browser-only processing
All streaming and logging happens locally in your browser session with no server-side payload storage.
Quick export for issue tracking
Copy or download the stream log to attach reproducible traces in tickets and incident timelines.
Common Use Cases
Useful across backend, frontend, QA, and operations workflows.
SSE API endpoint validation
Backend teams can quickly verify that a stream endpoint emits correctly formatted SSE frames and expected event names.
Real-time bug reproduction
QA engineers can capture live stream behavior and inspect payload timing when intermittent client update issues occur.
Heartbeat and reconnect checks
Observe keepalive or ping events to confirm stream health and understand how your endpoint behaves under connection drops.
Environment smoke testing
Compare staging and production SSE behavior from one UI before wiring events into your app state management.
Related Tools
React Native StyleSheet to CSS
Convert React Native StyleSheet objects into clean CSS classes with transform and spacing support. Free online React Native StyleSheet to CSS converter.
Port Number Reference
Look up the standard service associated with any port number with transport, category, and range filters plus CSV export. Free online port number reference.
Deep Link Builder
Build and test URI scheme links, universal links, and Android intent URLs for mobile apps. Free online deep link builder.
curl Command Builder
Build complete curl commands from a form with HTTP method, URL, headers, authentication (Basic Auth, Bearer, API key), and request body (JSON, form, multipart) - Free online curl builder
Push Notification Payload Builder
Build and validate APNs and FCM JSON push notification payloads with deep links, custom data fields, priority, and TTL controls. Free online push payload builder.
Sitemap XML Generator
Generate a valid sitemap.xml file online for free from a list of URLs. Configure change frequency, priority, and last modification date settings - Free online sitemap generator
Fetch / Axios Code Generator
Generate browser fetch or Axios JavaScript/TypeScript code from URL, method, headers, and body - supports async/await, auth, and TypeScript - Free online fetch code generator
LSI Keywords Generator
Find semantically related LSI keywords for your focus topics. Group keywords into intent clusters and generate optimized article outlines to improve your SEO rankings - Free online LSI keywords tool
Frequently Asked Questions
Important implementation details for EventSource testing in browser environments.
What is a Server-Sent Events tester?+
A Server-Sent Events tester is a client tool that opens an EventSource connection to an SSE endpoint and displays streamed events live. It helps you verify event formatting, custom event names, and connection stability without writing quick test scripts.
Can this tool connect to any SSE endpoint?+
It can connect to any valid HTTP or HTTPS endpoint that returns text/event-stream data and allows browser connections via CORS or same-origin policy. Connection behavior depends on your endpoint security and CORS configuration.
Can I inspect custom named events?+
Yes. Enter custom event names in the custom event field, and the tester will register listeners for those names in addition to standard message events.
Can I send custom headers with EventSource?+
No. Standard browser EventSource does not support arbitrary custom request headers. Use same-origin cookies, query tokens, or a proxy layer if your endpoint requires header-based auth.
Is the event data stored on a server?+
No. Streaming, display, and export happen locally in your browser. The tool does not upload or store your SSE payloads on Aback Tools servers.