Sync your labels to cloud storage

Automatically save labels to AWS S3



We strongly recommend that highly technical users (examples: IT professionals, software developers, or system administrators) are the ones who perform the steps outlined in this process.

Typically, after labeling your data with Encord, the labels are used to training your ML models. This process typically includes transferring your labels to cloud storage. To streamline this, follow the steps below to automatically save your labels to your cloud storage upon their creation:

  1. Create an IAM policy for a Lambda function.
  2. Paste the following JSON into the JSON policy editor, replacing <BUCKET_NAME> with the name of the S3 bucket you want to export your labels to.
	"Version": "2012-10-17",
	"Statement": [
			"Sid": "buckelabels",
			"Action": [
			"Effect": "Allow",
			"Resource": [
  1. Create an IAM role for Lambda, and attach the policy you created in Step 1.

  2. Create a new directory on your computer to store the components for your container image. The directory must include:

  • The lambda function script provided below. You must replace <s3_bucket_name> with your S3 bucket name. We recommend saving the script as
  • The docker file provided below.
  • A text file named access-key to store your private key. The key is used for authentication with Encord.



Creating a file called access-key to store your private key path is the simplest way, but not a secure way of ensuring the Lambda function can authenticate with Encord. Alternatives include, but are not limited to:

import json
import boto3
from encord import EncordUserClient

def lambda_handler(event, context):
    # Extract project_hash and label_hash from the webhook payload
    payload = event['payload']
    project_hash = payload['project_hash']
    label_hash = payload['label_hash']

    # Authenticate Encord user client.
    user_client = EncordUserClient.create_with_ssh_private_key(

    # Specify your S3 bucket name. Replace <s3_bucket_name> with your S3 bucket name
    s3_bucket_name = "<s3_bucket_name>"
    s3_client = boto3.client('s3')

    project = user_client.get_project(project_hash=project_hash)
    for label_rows in project.list_label_rows_v2(label_hashes=[label_hash]):
        # Download labels

        # Filename in S3 includes the label_hash
        s3_filename = f'{label_hash}_label_data.json'
        # Convert label_rows to JSON string
        label_data_json = json.dumps(label_rows.to_encord_dict())

        # Upload the JSON string directly to S3
        s3_client.put_object(Bucket=s3_bucket_name, Key=s3_filename, Body=label_data_json)

    return {
        "statusCode": 200,
        "body": json.dumps("Finished!")
RUN pip install boto3 
RUN pip install pyjson 
RUN pip install encord
RUN chmod 755 ${LAMBDA_TASK_ROOT}/
CMD ["lambda_function.lambda_handler"]
  1. Create a private ECR repository in AWS to store your container image. Record the path to the ECR repository you create.

  2. Create a Docker container image for the Lambda function. Use the command line to navigate to the directory you created in step 4. The following command shows an example with a tag containing a version number appended to the repository path:

docker build -t lambda-function-image:latest
  1. Push your container image to the private ECR repository you created in step 5. The following command shows an example with a tag containing a version number appended to the repository path:
docker push lambda-function-image:latest
  1. Create a Lambda function in AWS.
  • Select the Container image option.
  • Give the Lambda function a meaningful name.
  • Click Browse images and select the container image from your ECR repository.
  • Select the role you created in step 3 as the Execution role.
  1. Add a trigger for the Lambda function. Record the URL.

  2. In Encord, set up a new notification to send label information to your Lambda function, each time a task has reached the Complete stage of your workflow.

  • When creating the notification, include a webhook and enter the URL of the trigger you created in step 8. The payload sent out by the webhook can be viewed here.
  • Add a Task completed trigger. The webhook triggers your Lambda function when a task is annotated and has passed review.



Webhooks can be set up on individual workflow stages to send notifications when a task arrives at a specified workflow stage.