> That doesn't seem much better than having the browser poll the web server on a periodic basis... It could indeed be much better for performance. It means the

> That doesn't seem much better than having the browser poll the web server on a periodic basis... It could indeed be much better for performance. It means the polling happens over a (presumably) low-latency, high-throughput local datacenter connection, and not over the end-user's internet connection over which you have no control. But more importantly, SSE only defines the interface between the web browser and web server. Rather than polling a DB, you could just as well hook the web server up to a more sophisticated pubsub system (although PHP might not be the best choice for that). In that regard, SSE is no different from websockets; the main difference is that it's a simpler protocol to implement, and only works one-way.