Modal Sandboxes review

Modal Sandboxes rank fourth and suit teams that want sandboxes on the same platform as their models. The docs describe secure containers for LLM-generated or user-generated code, created from Python, JavaScript or Go, with exec calls that stream output, timeouts, volumes and bucket mounts. Two runtimes are offered: gVisor, which Modal calls suitable for most workloads, and a VM runtime with its own Linux kernel for jobs that need more. GPUs, memory snapshots and autoscaling come from the wider Modal platform, which also covers inference and training. The Starter plan costs $0 plus compute with $30 of monthly credits, up to 3 seats and 100 containers; Team is $250 a month with $100 credits and 5,000 containers. Sandbox CPU bills $0.00003942 per core per second because sandboxes are priced at non-preemptible rates, which Modal states is 3x list price. That makes it pricier per hour than Daytona or Northflank.

Who it is for

AI teams already training or serving models on Modal who want sandboxes, GPUs and RL rollouts on one bill.

Price

Starter $0 plus compute with $30 a month in free credits; Team $250 per month plus compute; sandbox CPU $0.00003942 per core per second.

Team: $250 + compute / month
Quoted from the vendor pricing page on November 9, 2026.

Key features

• Choice of gVisor runtime or a VM runtime with its own Linux kernel
• Python, JavaScript and Go SDKs
• Volumes and cloud bucket mounts inside sandboxes
• Memory snapshots for faster starts
• GPU access from the same platform

Strengths and weaknesses

• Strength: Starter plan includes $30 of compute every month
• Strength: Up to 100 containers on Starter and 5,000 on Team
• Strength: Startup and academic credit programs
• Weakness: Sandboxes bill at non-preemptible rates of 3x list price
• Weakness: Team plan costs $250 a month before compute
• Weakness: More setup than single-purpose sandbox APIs

Key facts

• Starter: $0 plus compute, $30 monthly credits, up to 3 seats, 100 containers
• Team: $250 a month plus compute, $100 monthly credits, 5,000 containers
• Sandbox CPU: $0.00003942 per core per second
• Sandbox memory: $0.00000667 per GiB per second
• Egress: 1 TiB a month included on Starter

Where it ranks

Modal Sandboxes is No. 4 in our Best AI Agent Sandboxes verdict.