@anvia/server

@anvia/server turns asynchronous Anvia events into HTTP streaming responses. It supports JSON Lines and Server-Sent Events, adds the correct transport headers, and can persist stream envelopes so a client can resume after navigation or a connection loss.

Use it at an HTTP route boundary. The agent or completion request produces events; this package only transports them.

Install

pnpm add @anvia/server @anvia/core

Return an agent stream

import type { UIStreamRequest } from '@anvia/core/ui'
import { createEventStream } from '@anvia/server'
import { supportAgent } from './support-agent'

export async function POST(request: Request) {
  const body = (await request.json()) as UIStreamRequest
  const promptRequest = supportAgent.prompt(body.messages)

  return createEventStream(promptRequest.stream(), {
    format: 'jsonl',
  })
}

JSONL is the default format. Set format: 'sse' when the client or hosting platform expects text/event-stream.

Key features

• createEventStream wraps any AsyncIterable in a streaming Response.
• createUIStreamResponse narrows the event type to Core's UIStreamEvent contract.
• createJsonlStream and createSseStream expose lower-level byte streams.
• createResumableStream assigns monotonically increasing event IDs and persists envelopes.
• resumeStreamEvents replays stored events and tails a run that is still active.
• ResumableStreamStore lets applications supply durable, shared persistence.

Common patterns

Keep generation outside the transport call

Create the prompt request first, then pass its stream to createEventStream. This makes cancellation, tracing, and testing easier to understand than hiding agent construction inside the response helper.

Forward request cancellation

The prompt request owns model execution. Use its cancellation API or the underlying provider signal as described in Errors and cancellation. The server helper consumes events; it does not decide when the agent should stop.

Use durable storage for resumable production streams

createMemoryResumableStreamStore is useful for local development and tests. It is process-local and disappears on restart, so production deployments with multiple workers should implement ResumableStreamStore against shared durable storage. See Resumable streams.

Preserve the wire format on both sides

Pair JSONL responses with readJsonlStream or the default @anvia/react transport. Pair SSE responses with readSseStream or format: 'sse' on the client.

Runtime compatibility

Field	Value
Package format	ESM
Required web APIs	Response, ReadableStream, TextEncoder, Headers
Anvia dependency	@anvia/core
Framework coupling	None

The package works in server runtimes that implement the standard Fetch and Web Streams APIs. Whether a hosting platform flushes streaming responses promptly is platform-specific; verify buffering and execution limits before production use.

Continue learning

• Server transport
• Completion streams
• Agent streams
• Resumable streams
• Run an agent in Studio

For exact exports and signatures, use the API reference. For release history, read the source changelog.