Which is better, Cloudflare Sandbox or AWS Lambda MicroVMs?
It depends on which platform the rest of your app runs on. For agents that mostly wait on a model and call an API from any backend, Runtime has the lowest cost: $0.64 for the benchmark, against $1.35 on Cloudflare and $4.20 on Lambda. A pause keeps files and memory. Pick Cloudflare Sandbox if your app already runs on Workers and needs sandboxes near its users. Pick Lambda MicroVMs if the work must stay inside AWS.
At a glance
| Cloudflare Sandbox | AWS Lambda MicroVMs | Runtime | |
|---|---|---|---|
| Isolation | A container in its own VM | Firecracker microVM | Firecracker microVM, own kernel |
| CPU | $0.072 per active vCPU-hour, 10 ms steps | $0.0997 per baseline vCPU-hour | $0.025 per vCPU-hour of measured CPU, with a small floor |
| Memory | $0.009 per provisioned GiB-hour, 3 GiB per vCPU at least | $0.0132 per GB-hour, 2 GB per vCPU | $0.0075 per reserved GiB-hour |
| Sizes | Up to 4 vCPUs, 12 GiB and 20 GB | A 4 vCPU, 8 GB baseline | 16 vCPUs and 64 GiB, paid |
| Idle | Filesystem-only snapshots; processes restart | Suspends after an idle time you set; 8 hours of life at most | Pause keeps memory while you have credit |
| Driven from | A Cloudflare Worker | The AWS API | API, CLI, SDKs or MCP |
How the two platforms differ
Each is the sandbox of a larger cloud, and each fits best inside it. Cloudflare's runs from a Worker, near users, and bills only active CPU. Lambda's lives with IAM and VPCs, and bills its baseline. Both tie memory to CPU: at least 3 GiB per vCPU on Cloudflare, and exactly 2 GB on Lambda. Runtime lets memory and CPU be chosen separately.
Cost for the same job
The benchmark runs 60 seconds a run, with 6 GiB and a 12 GB disk on Cloudflare, and a 4 GB baseline on Lambda:
- CPU
- 1,000 × 20 s × $0.000020
- $0.40
- Memory
- 1,000 × 60 s × 6 × $0.0000025
- $0.90
- Disk
- 1,000 × 60 s × 12 × $0.00000007
- $0.05
- CPU
- 1,000 × 60 s × 2 × $0.0000276944
- $3.32
- Memory
- 1,000 × 60 s × 4 × $0.0000036667
- $0.88
- CPU
- 1,000 × 20 s / 3,600 × $0.025
- $0.14
- Memory
- 1,000 × 60 s / 3,600 × 4 × $0.0075
- $0.50
With both CPUs busy for the whole minute, the job costs $3.35 on Cloudflare, $4.20 on Lambda and $1.33 on Runtime.
Which one to pick
- Cloudflare Sandbox for apps already on Workers that want sandboxes near their users.
- Lambda MicroVMs for work that must stay inside AWS.
- Runtime for the lowest cost whether the code waits or works, and for files and memory that survive a pause.
See Runtime vs Cloudflare Sandbox and Runtime vs AWS Lambda MicroVMs.
Runtime Cloud
Runtime costs 53% less than Cloudflare and 85% less than Lambda MicroVMs. The benchmark, 1,000 runs of a minute on 2 vCPU and 4 GiB doing 20 CPU-seconds each, costs $1.35 on Cloudflare Sandbox (priced at 6 GiB, its minimum for two vCPUs), $4.20 on AWS Lambda MicroVMs and $0.64 on Runtime.
Run npx withruntime login to get started free, then use the migration guide to move a Worker or Lambda project.
Sources
Cloudflare sandbox lifetime, snapshot behavior checked 25 October 2026. Cloudflare rates checked 25 October 2026; Lambda MicroVMs rates checked 25 October 2026.
Cloudflare Containers pricing, Containers limits and instance types
Runtime pricing
Facts on this page were checked on 26 October 2026.