@cramforce: "This is based on `resumable-stream` which you c..."

This is based on `resumable-stream` which you can find on npm! A core feature is that while it uses Redis, the actual Redis usage is minimal unless you actually need to resume a stream (which should be rare in practice). It supports: - Clients resuming streams on network interruption - Multiple browser tabs following the same underlying stream - Multiple users following the same stream

import { createResumableStreamContext } from "resumable-stream";
import { after } from "next/server";

const streamContext = createResumableStreamContext({
waitUntil: after,
// Optionally pass in your own Redis publisher and subscriber
});

export async function GET(req: NextRequest, { params }: { params: Promise<{ streamId: string }> }) {
const { streamId } = await params;
const resumeAt = req.nextUrl.searchParams.get("resumeAt");
const stream = await streamContext.resumableStream(
streamId,
makeTestStream,
resumeAt ? parseInt(resumeAt) : undefined
);
if (!stream) {
return new Response("Stream is already done", {
status: 422,
});
}
return new Response(strean, {
headers: {
"Content-Type": "text/event-stream",
},
});
}

Guillermo Rauch

@rauchg

The @vercel Chat SDK now features stream resumption. This makes AI conversations resilient to network hiccups and reloading or sharing a chat mid-generation. This is especially valuable for long responses (e.g.: Deep Research). No proprietary APIs, no sticky load balancing, just

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2:32 PM · May 10, 2025

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