Beyond Kubernetes at Modal: How to Scale 1 Million Concurrent Sandboxes in Seconds
Modal scaled sandboxes to 1M concurrent instances. Here's the infrastructure that made it possible.
Why it matters
Modal's rebuild of sandbox infrastructure from the ground up reveals how AI/code execution platforms are solving the hardware and orchestration challenges of agentic workloads at scale — a critical dependency for agent reliability and deployment.
The key facts
10 to know1 million concurrent sandboxes supported
Tens of thousands of sandbox creations per second
Infrastructure rebuilt from the ground up
Authors: Colin Weld and Connor Adams, staff engineers at Modal
Published: September 2026
Modal rebuilt sandbox infrastructure from the ground up
Targets: 1 million concurrent sandboxes
Throughput: tens of thousands of sandbox creations per second
Staff engineers: Colin Weld, Connor Adams
Article describes moving beyond Kubernetes for sandbox orchestration
Go to the source
InfoQ AI/MLinfoq.com
Publisher excerpt: In a recent article, Colin Weld and Connor Adams, staff engineers at Modal, describe how they rebuilt their sandbox infrastructure from the ground up to support millions of concurrent sandboxes and tens of thousands of sandbox creations per second. By Sergio De Simone