SSE FAQ

sse_survival_guide.md

This is just a stub doc for collecting any SSE related tips/tricks/considerations others in the Datastar community want to share. While it will likely serve as a helpful resource itself, the content will be used to author a more user friendly doc or artifact to reference when learning and leveraging SSE.

SSE FAQ

Are there any SSE gotchas?

There are some known gotchas for SSE documented here:

• https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events
• https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events#listening_for_custom_events

1. Compression should be done at the application level, not by a reverse proxy. Otherwise, depending on the frequency and content size of your event payloads, number of simultaneous connections, and their duration, you could potentially send large amounts of unnecessary data between your application and the reverse proxy. It will increase memory usage in both places, increasing server resource demands.

What about if the reverse proxy is on the same server - eg caddy in front of your app?

2. Brotli compression should be preferred and used, if possible, as it can enable insane compression ratios (think 100s:1), if your response is well suited to it (ie the structure of your HTML is fairly similar across events and the SSE stream is long-lasting). This can result in barely any data transfer to the client over the lifetime of the connection.

What about zstd for browsers that support it?

fyi
there is a link to this gist from https://github.com/alvarolm/datastar-resources/blob/main/docs/considerations.md