wrangler K2 producer bindings write to existing streams

Introduced 2026-09-30 · score 0.92

HOW TO USE IT

When producing events from a Worker to an existing K2 stream, add its ID and a binding name under `k2` in Wrangler config, then call `env.<BINDING>.send(records)` and check `result.success`.

{
  "k2": [
    {
      "binding": "<BINDING>",
      "stream": "<32-character-lowercase-hex-stream-id>"
    }
  ]
}

const result = await env.<BINDING>.send([
  {
    content: new TextEncoder().encode("<EVENT_PAYLOAD>"),
    headers: { event: "<EVENT_NAME>" }
  }
]);
if (!result.success) {
  console.error(`Produce failed: ${result.error.message}`);
}

npx wrangler types

WHY THIS HELPS

Configure a Worker to produce events to an existing K2 stream during development or deployment.

REQUIREMENTS AND LIMITATIONS

Version: 4.145.0
Availability: Beta
k2[].binding (required): Worker variable name for the binding, such as `env.ORDERS`.
k2[].stream (required): 32 lowercase hexadecimal stream ID; stream must be in the same account as the Worker.
send(records)[].content (required): Record payload as `ArrayBuffer` or `Uint8Array`; all records in a batch must use the same type.
send(records)[].headers: Metadata map with string keys and string values.
Prerequisite: K2 is available on the Workers Paid plan; it is in public beta.
Prerequisite: The K2 Workers binding input must be enabled on the stream; it is enabled by default when omitted at stream creation.
Prerequisite: Run `npx wrangler types` after adding the binding to generate the Env type.
K2 requires an enabled account.
Deployment credentials need Worker deployment and K2 configuration-read access.
Existing OAuth users should run `wrangler login` again to grant the new permissions.
Development always uses a real K2 stream and may incur usage charges; no local simulator is provided.
Batches use either all `ArrayBuffer` or all `Uint8Array` content.
Check the returned `success` value, handle rejected RPC promises, and retry only when the returned error explicitly allows it.
`remote: false` is rejected.
Consumption is not part of this Worker binding.

FIRST-PARTY EVIDENCE

Check the installed version and the source before using it. Entry JSON

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wrangler K2 producer bindings write to existing streams