SSE Test Client
Interactive Server-Sent Events (SSE) testing client for one-way event streaming with automatic reconnection. Demonstrates efficient server-to-client real-time communication patterns.
Overview
A comprehensive SSE testing playground built to demonstrate and test server-to-client event streaming. Shows how Server-Sent Events enable efficient one-way real-time communication with automatic reconnection capabilities.
Key Features
- Real-Time Event Streaming: Live server-to-client event delivery
- Automatic Reconnection: Built-in reconnection with exponential backoff
- Event History: Complete log of all received events with timestamps
- Connection Status: Real-time connection state monitoring
- Multiple Event Types: Support for different event categories
- Interactive Interface: Clean UI for monitoring event stream
Technical Implementation
Built with Hono’s streaming support and the EventSource API, providing reliable one-way communication with minimal overhead.
Core Technologies
- EventSource API: Native browser API for SSE connections
- Backend: Hono framework with streaming response support
- Type Safety: Full TypeScript integration for event contracts
- Connection Management: Automatic reconnection handling
- Frontend: Vanilla JavaScript for lightweight implementation
Architecture Highlights
- HTTP-based protocol using standard web technologies
- Automatic reconnection on connection loss
- Event ID tracking for reliable delivery
- Long-lived HTTP connections with keep-alive
- Simple text-based protocol for efficiency
SSE vs WebSocket
When to Use SSE:
- One-way communication from server to client
- Simpler implementation than WebSocket
- Automatic reconnection built into browser
- Works through most proxies and firewalls
- Lower overhead for server-to-client updates
SSE Advantages:
- Built on HTTP/HTTPS (no special protocol)
- Automatic reconnection with event ID tracking
- Simpler server implementation
- Better for unidirectional data flow
- Native browser support with EventSource API
Use Cases
- Live Notifications: Push notifications from server to client
- Real-Time Dashboards: Live data updates for monitoring dashboards
- News Feeds: Streaming content updates
- Stock Tickers: Live price updates
- Activity Streams: Real-time activity logs and audit trails
- Progress Updates: Long-running operation status updates
Technical Highlights
- Production-ready SSE implementation
- Automatic reconnection with last event ID
- Memory-efficient streaming
- Support for named events
- Connection health monitoring
- Cross-origin support (CORS)
Real-Time Capabilities
- Efficient one-way communication
- Low latency event delivery
- Automatic buffering and retry
- Event ordering guarantees
- Connection persistence with keep-alive