Deno Sandbox
Last verified 2026-08-09
Deno Sandbox is Deno Deploy's isolate-based environment for executing untrusted or model-generated code, including code that calls external APIs with real credentials. It uses V8 isolates for millisecond starts and bills on actual CPU time consumed, not wall-clock, so idle time is not charged. It ships as part of the Deno Deploy platform.
Key specs
| Isolation | V8 isolate |
| Price / vCPU-hr | $0.05 |
| Pricing model | Usage-based (CPU time), via Deno Deploy |
| GPU | No |
| Persistence | Volume storage ($0.20/GiB-month); isolate compute |
| Languages | JavaScript/TypeScript |
| MCP support | n/a |
| Deployment | Managed (Deno Deploy) |
| Free tier | Included in Deno Deploy Pro (40 CPU-h, 1000 GB-h, 5 GiB volume) |
| CPU time | $0.05/CPU-hr |
| Memory | $0.016/GiB-hr |
| Volume | $0.20/GiB-month |
Strengths
- V8 isolates give millisecond starts
- Billed on CPU time, not wall-clock
- Included in Deno Deploy
- Built for untrusted / model-generated code
Trade-offs
- JavaScript/TypeScript runtime focus
- No GPU
- Tied to the Deno Deploy platform
Best for: Running untrusted JS/TS or LLM-generated code inside a Deno Deploy app, billed only for CPU time used.
How Deno Sandbox works
Deno Sandbox runs untrusted or model-generated code in V8 isolates, the same lightweight isolation model behind Deno Deploy, which start in milliseconds rather than booting a VM or container. It is designed for the case where LLM-generated code, or code written by your users, needs to call external APIs with real credentials without a human in the loop. It runs JavaScript and TypeScript and ships as part of the Deno Deploy platform rather than as a standalone service.
Pricing in practice & watch-outs
Deno bills on CPU time actually consumed rather than wall-clock, at $0.05 per CPU-hour, $0.016 per GiB-hour of memory and $0.20 per GiB-month of volume storage, with a block of each included in the Deno Deploy Pro plan. Charging for CPU time, not elapsed time, means idle sandboxes waiting on I/O do not run up the bill. The main constraints are the runtime and the platform coupling: it is a JavaScript/TypeScript environment, there is no GPU, and it lives inside Deno Deploy rather than as a portable service.
Head-to-head
Alternatives to Deno Sandbox
See the full Deno Sandbox alternatives comparison →
Sources: Deno Sandbox ↗ · Introducing Deno Sandbox ↗
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