Labelbox documentation

Create CORS headers

CORS (Cross-origin resource sharing) is a browser mechanism that enables restricted access across domain boundaries. In this case, CORS allows Labelbox to request access to the resources in your S3 bucket.

The Labelbox app requires that assets be served with CORS headers and allow access from the following Labelbox origins: and

Follow these steps to set up a CORS header for your S3 bucket.

  1. In your AWS account, go to your S3 Management Console.

  2. Click the bucket name in the list of buckets.

  3. Go to the Permissions tab.

  4. In the Cross-origin resource sharing (CORS) section, click Edit.

  5. Paste the following configuration in the text field.

            "AllowedHeaders": [
            "AllowedMethods": [
            "AllowedOrigins": [
            "ExposeHeaders": []
  6. Click Save changes.

For more details on setting up CORS for your S3 bucket, see these AWS docs.