# Modal vs AWS Lambda MicroVMs: serverless sandboxes compared

Modal isolates sandboxes with gVisor and Lambda MicroVMs with Firecracker. For 1,000 one-minute 2 vCPU runs, Modal costs $3.97 and Lambda $4.20.

**Runtime runs the same work for 84% less than Modal and 85% less than Lambda
MicroVMs.** Both rivals come from serverless functions and bill a sandbox for
what it reserved: Modal the larger of its request and its use, Lambda its
baseline. Runtime measures CPU, so the benchmark, 1,000 runs of a 2 vCPU,
4 GiB sandbox with 20 CPU-seconds of work, costs $0.64 there.

## At a glance

|           | Modal Sandboxes                                          | AWS Lambda MicroVMs            | Runtime                                                  |
| --------- | -------------------------------------------------------- | ------------------------------ | -------------------------------------------------------- |
| Isolation | gVisor, a user-space kernel                              | Firecracker microVM            | Firecracker microVM, own kernel                          |
| CPU       | $0.1419 per physical core-hour (2 vCPUs), request or use | $0.0997 per baseline vCPU-hour | $0.025 per vCPU-hour of measured CPU, with a small floor |
| Memory    | $0.0240 per GiB-hour, request or use                     | $0.0132 per GB-hour            | $0.0075 per reserved GiB-hour                            |
| Lifetime  | Up to 24 hours; snapshots carry state beyond             | State kept up to 8 hours       | Leases extended as needed, or `persistent`               |
| Plan      | Starter $0 with $30 a month; Team $250 a month           | None; an AWS account           | None; prepaid credit from $10                            |
| GPUs      | Yes, beside Modal functions                              | No                             | No                                                       |

## A shared lineage, different kernels

Modal and Lambda both grew sandboxes out of a functions platform, so both fit
teams already deploying there. The difference that matters for untrusted agent
code is the boundary: gVisor intercepts system calls in a user-space kernel,
while a Lambda MicroVM, like a Runtime sandbox, runs its own guest kernel under
a hypervisor. See [gVisor vs Firecracker](/compare/firecracker-vs-gvisor).

## Cost for the same job

1,000 runs, 60 seconds each, 20 CPU-seconds of work, 2 vCPU and 4 GiB (one
physical core on Modal, a 4 GB baseline on Lambda):

```
Modal     CPU    1,000 × 60 s × 1 core × $0.00003942           = $2.37
          Memory 1,000 × 60 s × 4 × $0.00000667                = $1.60
          Total                                                  $3.97

Lambda    CPU    1,000 × 60 s × 2 × $0.0000276944              = $3.32
          Memory 1,000 × 60 s × 4 × $0.0000036667              = $0.88
          Total                                                  $4.20

Runtime   CPU    1,000 × 20 s / 3,600 × $0.025                = $0.14
          Memory 1,000 × 60 s / 3,600 × 4 × $0.0075           = $0.50
          Total                                                  $0.64
```

For 100,000 runs a month: $396.60 on Modal, $420.33 on Lambda, $63.89 on
Runtime. Kept busy for the whole minute on both CPUs, the job still costs $3.97 on Modal and $4.20 on Lambda, and $1.33 on Runtime.

## Which one to pick

- **Modal** when sandboxes sit beside GPU functions and scheduled jobs.
- **Lambda MicroVMs** when the rest of the system is on AWS and must stay
  inside your VPC and IAM.
- **Runtime** for Firecracker at a sixth of either bill, sandboxes up to 16
  vCPUs and 64 GiB, and pauses that keep memory for up to a year.

More: [Runtime vs Modal](/docs/modal-sandbox-alternative),
[Runtime vs AWS Lambda MicroVMs](/docs/aws-lambda-microvms-alternative).

## Sources

Modal rates checked 23 September 2026; Lambda rates checked 25 September 2026.

- [Modal pricing](https://modal.com/pricing), [Modal resources and billing](https://modal.com/docs/guide/resources)
- [AWS Lambda pricing](https://aws.amazon.com/lambda/pricing/), [Lambda MicroVMs](https://aws.amazon.com/lambda/lambda-microvms/)
- Runtime [pricing](/docs/pricing)

Facts on this page were checked on 25 September 2026.