Hi. I suppose that the pass to the template file is incorrect. When localstack executes the script it searches for the files inside the container not on the PC file system. So I suggest creating a Docker volume, placing the template inside, and then refer it in your script. A similar approach is explained here https://aws.plainenglish.io/send-messages-to-sqs-during-localstack-initialization-e5396f67bc5f. Although it is about SQS there you can find an example of how to refer to a file inside the script.