Writing to streams

Send events to streams using Worker bindings or HTTP endpoints for client-side applications and external systems.

Send via Workers

Worker bindings provide a secure way to send data to streams from Workers without managing API tokens or credentials.

Configure pipeline binding

Add a pipeline binding to your Wrangler file that points to your stream:

{
  "pipelines": [
    {
      "pipeline": "<STREAM_ID>",
      "binding": "STREAM"
    }
  ]
}

[[pipelines]]
pipeline = "<STREAM_ID>"
binding = "STREAM"

Workers API

The pipeline binding exposes a method for sending data to your stream:

`send(records)`

Sends an array of JSON-serializable records to the stream. Returns a Promise that resolves when records are confirmed as ingested.

export default {
  async fetch(request, env, ctx) {
    const events = await request.json();

    await env.STREAM.send(events);

    return new Response("Events sent");
  },
};

export default {
  async fetch(request, env, ctx): Promise<Response> {
    const events = await request.json<Record<string, unknown>[]>();

    await env.STREAM.send(events);

    return new Response("Events sent");
  },
} satisfies ExportedHandler<Env>;

Typed pipeline bindings

When a stream has a defined schema, running wrangler types generates schema-specific TypeScript types for your pipeline bindings. Instead of the generic Pipeline<PipelineRecord>, your bindings get a named record type with full autocomplete and compile-time type checking. Refer to the wrangler types documentation to learn more.

Generated types

After running wrangler types, the generated worker-configuration.d.ts file contains a named record type inside the Cloudflare namespace. The type name is derived from the stream name (not the binding name), converted to PascalCase with a Record suffix.

Below is an example of what generated types look like in worker-configuration.d.ts for a stream named ecommerce_stream:

declare namespace Cloudflare {
  type EcommerceStreamRecord = {
    user_id: string;
    event_type: string;
    product_id?: string;