Workers API

This guide details the Pipelines API within Cloudflare Workers.

Send data to a Pipeline from a Worker

Pipelines exposes an API directly to your Workers scripts via the bindings concept. Bindings allow you to securely send data to a Pipeline without having to manage API keys or clients.

You can bind to a Pipeline by defining a [[pipelines]] binding within your Wrangler configuration. For example:

wrangler.toml

#:schema node_modules/wrangler/config-schema.json
name = "pipeline-starter"
main = "src/index.ts"
compatibility_date = "2025-04-01"

[[pipelines]]
pipeline = "<MY-PIPELINE-NAME>" # The name of your Pipeline
binding = "MY_PIPELINE" # The binding name, accessed using env.MY_PIPELINE

wrangler.json

{
  "name": "pipeline-starter",
  "main": "src/index.ts",
  "compatibility_date": "2025-04-01",
  "pipelines": [
    {
      "pipeline": "<MY-PIPELINE-NAME>",
      "binding": "MY_PIPELINE"
    }
  ]
}

Pipeline

A binding which allows a Worker to send messages to a Pipeline.

interface Pipeline<PipelineRecord> {
  send(records: PipelineRecord[]): Promise<void>;
}

• send(records): Promise<void>

  • Sends a message to the Pipeline. The body must be an array of objects supported by the structured clone algorithm ↗.
  • When the promise resolves, the message is confirmed to be stored by the Pipeline.

Note

When running your Worker locally, Pipelines are partially simulated. Worker code which sends data to a Pipeline will execute successfully. However, the full Pipeline, including batching & writing to R2, will not be executed locally.

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