[samwillis]

This is one of the main use cases we are building "Durable Streams" for, it's an open source spec for a resumable and durable stream protocol. It's essentially an append only log with a http api.

https://github.com/durable-streams/durable-streams

https://electric-sql.com/blog/2025/12/09/announcing-durable-...

When we built ElectricSQL we needed a resumable and durable stream of messages for sync and developed a highly robust and scalable protocol for it. We have now taken that experience and are extracting the underlying transport as an open protocol. This is something the industry needs, and it's essential that it's a standard that portable between provider, libraries and SDKs.

The idea is that a stream is a url addressable entity that can be read and tailed, using very simple http protocol (long polling and a SSE-like mode). But it's fully resumable from a known offset.

We've been using the previous iteration of this as the transport part of the electric sync protocol for the last 18 months. It's very well tested, both on servers, in the browser, but importantly in combination with CDNs. It's possible to scale this to essential unlimited connections (we've tested to 1 million) by request collapsing in the CDN, and as it's so cacheable it lifts a lot of load of your origin when a client reconnect from the start.

For the LLM use case you will be able to append messages/tokens directly to a stream via a http post (we're working on specifying a websocket write path) and the client just tails it. If the user refreshes the page it will just read back from the start and continue tailing the live session. Avoids appending tokens to a database in order to provide durability.