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  1. Products
  2. Workers
  3. Configuration
  4. Multipart upload metadata

Multipart upload metadata

If you’re using the Workers Script Upload API or Version Upload API directly, multipart/form-data uploads require you to specify a metadata part. This metadata defines the Worker’s configuration in JSON format, analogue to the wrangler.toml file.

​​ Sample metadata

metadata
{
  "main_module": "main.js",
  "bindings": [
    {
      "type": "plain_text",
      "name": "MESSAGE",
      "text": "Hello, world!"
    }
  ],
  "compatibility_date": "2021-09-14"

}

​​ Attributes

The following attributes are configurable at the top-level.

  • main_module string required

    • The part name that contains the module entry point of the Worker that will be executed. For example, main.js.

  • bindings array[objec] optional

  • placement object optional

    • Smart placement object for the Worker.
    • mode field only supports smart for automatic placement.

  • compatibility_date string optional

    • Compatibility Date indicating targeted support in the Workers runtime. Backwards incompatible fixes to the runtime following this date will not affect this Worker. Highly recommended to set a compatibility_date, otherwise if on upload via the API, it defaults to the oldest compatibility date before any flags took effect (2021-11-02).

  • compatibility_flags array[string] optional

    • Compatibility Flags that enable or disable certain features in the Workers runtime. Used to enable upcoming features or opt in or out of specific changes not included in a compatibility_date.

  • usage_model string optional

    • Usage model to apply to invocations, only allowed value is standard.

​​ Additional attributes: Workers Script Upload API

For immediately deployed uploads, the following additional attributes are configurable at the top-level.

  • migrations array[object] optional

  • logpush boolean optional

    • Whether Logpush is turned on for the Worker.

  • tail_consumers array[object] optional

    • Tail Workers that will consume logs from the attached Worker.

  • tags array[string] optional

    • List of strings to use as tags for this Worker.

​​ Additional attributes: Version Upload API

For version uploads, the following additional attributes are configurable at the top-level.

  • annotations object optional

    • Annotations object specific to the Worker version.
    • workers/message specifies a custom message for the version.
    • workers/tag specifies a custom identifier for the version.

​​ Bindings

Workers can interact with resources on the Cloudflare Developer Platform using bindings. Refer to the JSON example below that shows how to add bindings in the metadata part.

metadata
{
  "bindings": [
    {
      "type": "ai",
      "name": "<VARIABLE_NAME>"
    },
    {
      "type": "analytics_engine",
      "name": "<VARIABLE_NAME>",
      "dataset": "<DATASET>"
    },
    {
      "type": "browser_rendering",
      "name": "<VARIABLE_NAME>"
    },
    {
      "type": "d1",
      "name": "<VARIABLE_NAME>",
      "id": "<D1_ID>"
    },
    {
      "type": "durable_object_namespace",
      "name": "<VARIABLE_NAME>",
      "class_name": "<DO_CLASS_NAME>"
    },
    {
      "type": "hyperdrive",
      "name": "<VARIABLE_NAME>",
      "id": "<HYPERDRIVE_ID>"
    },
    {
      "type": "kv_namespace",
      "name": "<VARIABLE_NAME>",
      "namespace_id": "<KV_ID>"
    },
    {
      "type": "mtls_certificate",
      "name": "<VARIABLE_NAME>",
      "certificate_id": "<MTLS_CERTIFICATE_ID>"
    },
    {
      "type": "plain_text",
      "name": "<VARIABLE_NAME>",
      "text": "<VARIABLE_VALUE>"
    },
    {
      "type": "queue",
      "name": "<VARIABLE_NAME>",
      "queue_name": "<QUEUE_NAME>"
    },
    {
      "type": "r2_bucket",
      "name": "<VARIABLE_NAME>",
      "bucket_name": "<R2_BUCKET_NAME>"
    },
    {
      "type": "secret_text",
      "name": "<VARIABLE_NAME>",
      "text": "<SECRET_VALUE>"
    },
    {
      "type": "service",
      "name": "<VARIABLE_NAME>",
      "service": "<SERVICE_NAME>",
      "environment": "production"
    },
    {
      "type": "tail_consumer",
      "service": "<WORKER_NAME>"
    },
    {
      "type": "vectorize",
      "name": "<VARIABLE_NAME>",
      "index_name": "<INDEX_NAME>"
    },
    {
      "type": "version_metadata",
      "name": "<VARIABLE_NAME>"
    }
  ]

}