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AWS SDK for Python (Boto3)

Boto3 is the Amazon Web Services (AWS) Software Development Kit (SDK) for Python, which allows Python developers to write software that makes use of AWS services.

You can easily create a boto3 client that interacts with your LocalStack instance. The example below creates a boto3 client that lists all available Lambda functions:

import boto3

endpoint_url = "http://localhost.localstack.cloud:4566"
# alternatively, to use HTTPS endpoint on port 443:
# endpoint_url = "https://localhost.localstack.cloud"

def main():
    client = boto3.client("lambda", endpoint_url=endpoint_url)
    result = client.list_functions()
    print(result)

if __name__ == "__main__":
    main()
note

If you're connecting from within a Python Lambda function handler in LocalStack, you can create a default client without configuring the endpoint_url - LocalStack will automatically forward the invocations to the local API endpoints.

client = boto3.client("lambda")
...

Alternatively, if you prefer to (or need to) set the endpoints directly, you can use the environment variable AWS_ENDPOINT_URL, which is available when executing user code (e.g., Lambda functions) in LocalStack:

import os
client = boto3.client("lambda", endpoint_url=os.getenv("AWS_ENDPOINT_URL"))
...

Further Material:​