Vercel AI SDK

Use @durable-streams/aisdk-transport to make Vercel AI SDK useChat generations durable and resumable and shareable across tabs, devices, users and agents.

This is the integration to use when you want a chat generation to survive refreshes and reconnect cleanly to the same stream. It plugs into the AI SDK's transport layer, so you can keep the normal useChat flow while swapping in a durable transport.

Install

pnpm add @durable-streams/aisdk-transport

Client

Swap the default transport for createDurableChatTransport, following the same transport model documented in the AI SDK transport docs:

import { useChat } from "@ai-sdk/react"
import { createDurableChatTransport } from "@durable-streams/aisdk-transport"

const transport = createDurableChatTransport({ api: "/api/chat" })
const chat = useChat({ transport, resume: true })

Server

Wrap the AI SDK UI message stream with toDurableStreamResponse:

import { toDurableStreamResponse } from "@durable-streams/aisdk-transport"

return toDurableStreamResponse({
  source: result.toUIMessageStream(),
  stream: {
    writeUrl: buildWriteStreamUrl(streamPath),
    readUrl: buildReadProxyUrl(request, streamPath),
    headers: DURABLE_STREAMS_WRITE_HEADERS,
  },
})

The server writes AI SDK chunks into Durable Streams and returns the read URL through Location and { streamUrl }.

Resume flow

For refresh-safe generations:

1. Persist the active stream id for the chat while generation is in progress.
2. Add a reconnect endpoint such as GET /api/chat/:id/stream.
3. Return 204 when there is no active generation, or 200 plus Location and { streamUrl } when there is one.
4. Enable resume: true in useChat.

Example

See the working example in:

• Package README
• Example app