# Fly Sprites vs AWS Lambda MicroVMs: persistent sandboxes and bursts

Sprites meter CPU used and memory in use; Lambda MicroVMs bill a baseline. On the 2 vCPU benchmark Sprites cost $3.31 and Lambda $4.20.

**Runtime is 81% cheaper than Sprites and 85% cheaper than Lambda MicroVMs for
an agent that waits.** 1,000 one-minute runs of a 2 vCPU, 4 GiB sandbox, 20
CPU-seconds apiece, cost $3.31 on Fly Sprites, $4.20 on AWS Lambda MicroVMs
and $0.64 on Runtime.

## At a glance

|           | Fly Sprites                                    | AWS Lambda MicroVMs                 | Runtime                                                  |
| --------- | ---------------------------------------------- | ----------------------------------- | -------------------------------------------------------- |
| Isolation | Firecracker microVM                            | Firecracker microVM                 | Firecracker microVM, own kernel                          |
| CPU       | $0.07 per CPU-hour of measured CPU             | $0.0997 per baseline vCPU-hour      | $0.025 per vCPU-hour of measured CPU, with a small floor |
| Memory    | $0.04375 per GB-hour of memory in use          | $0.0132 per GB-hour                 | $0.0075 per reserved GiB-hour                            |
| Disk      | 100 GB, kept always; $0.02 per GB-month asleep | In the snapshot, $0.08 per GB-month | Included while running; $0.08 per GB-month paused        |
| Lifetime  | Persistent; pauses itself                      | State kept up to 8 hours            | Leases extended, `persistent`, pauses up to 365 days     |

## Measured CPU, costly memory

Sprites and Runtime both charge CPU only while it works, which is why Sprites'
CPU line here is 39 cents against Lambda's $3.32. Memory reverses it: at
$0.04375 per GB-hour, Sprites' memory costs more than three times Lambda's.
Runtime's measured CPU comes with memory at $0.0075 per GiB-hour.

## Cost for the same job

The benchmark, 60 seconds a run, with 4 GB of memory in use on Sprites and a
4 GB baseline on Lambda:

```
Sprites  CPU    1,000 × 20 s / 3,600 × $0.07                  = $0.39
         Memory 1,000 × 60 s / 3,600 × 4 × $0.04375           = $2.92
         Total                                                  $3.31

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
```

Kept busy for the whole minute on both CPUs, the job would be $5.25 on Sprites, $4.20 on Lambda and $1.33 on Runtime.

## Which one to pick

- **Fly Sprites** for a personal, always-there computer with a large disk
  that sleeps for pennies.
- **Lambda MicroVMs** for bursts that must run inside AWS.
- **Runtime** for agents at the lowest bill, busy or idle, with memory kept
  across pauses.

See [Runtime vs Fly.io](/docs/fly-alternative) and
[Runtime vs AWS Lambda MicroVMs](/docs/aws-lambda-microvms-alternative).

## Sources

Fly Sprites rates checked 23 September 2026; Lambda MicroVMs rates checked 25 September 2026.

- [Fly.io pricing](https://fly.io/pricing/), [Sprites](https://fly.io/sprites/)
- [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.