Why Substack moved their AI and ML pipelines to Modal

What this post added

This post details Substack's migration of their AI and ML pipelines from AWS SageMaker to Modal. It highlights the challenges faced with SageMaker, such as convoluted developer experience, difficulties in code collaboration, and slow container startup times. The post then describes how Substack leveraged Modal's features, including its natural iteration flow, autoscaling capabilities, and native storage primitives (network volumes and key-value stores), to build a faster and more flexible ML workflow. This includes a full fine-tune -> validation -> deployment process, enabling rapid development and deployment of recommendation models and other ML applications.