Fly Sprites vs Freestyle: persistent computers for agents

Sprites and Freestyle VMs both persist between sessions. Sprites meter use; Freestyle bills allocation. The benchmark: $3.31 on Sprites, $2.25 on Freestyle.

Runtime costs 81% less than Sprites and 72% less than Freestyle for an agent that waits. 1,000 runs of a minute on 2 vCPU and 4 GiB, 20 CPU-seconds each: $3.31 on Fly Sprites, $2.25 on Freestyle, $0.64 on Runtime.

At a glance

	Fly Sprites	Freestyle	Runtime
Isolation	Firecracker microVM	Full Linux virtual machines	Firecracker microVM, own kernel
CPU	$0.07 per CPU-hour of measured CPU	$0.04032 per allocated vCPU-hour	$0.025 per vCPU-hour of measured CPU, with a small floor
Memory	$0.04375 per GB-hour of memory in use	$0.0129 per GiB-hour	$0.0075 per reserved GiB-hour
Asleep	Disk at $0.02 per GB-month	Storage at $0.000086 per GiB-hour	$0.08 per GB-month, memory included
SDKs	JavaScript, Python, Go, Elixir	TypeScript	JavaScript and Python, CLI and MCP

Where the money goes

Sprites charge little for CPU because they measure it, but their memory rate is more than three times Freestyle's, and memory is most of this job. Freestyle bills its lower rates on everything allocated, idle or not. Runtime pairs measured CPU with the lowest memory rate of the three.

Cost for the same job

The benchmark, 60 seconds a run, with 4 GB in use on Sprites and a 32 GiB disk on Freestyle:

TextSprites    CPU    1,000 × 20 s / 3,600 × $0.07                  = $0.39           Memory 1,000 × 60 s / 3,600 × 4 × $0.04375           = $2.92           Total                                                  $3.31Freestyle  CPU    1,000 × 60 s / 3,600 × 2 × $0.04032           = $1.34           Memory 1,000 × 60 s / 3,600 × 4 × $0.0129            = $0.86           Disk   1,000 × 60 s / 3,600 × 32 × $0.000086         = $0.05           Total                                                  $2.25Runtime    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

Were both CPUs busy for the whole minute, the job would cost $5.25 on Sprites, $2.25 on Freestyle and $1.33 on Runtime.

Which one to pick

• Fly Sprites for a personal machine with a 100 GB disk that sleeps cheaply.
• Freestyle for agent VMs with live forks, up to 32 vCPUs on Pro.
• Runtime for the lowest bill busy or waiting, and a Python SDK as well as JavaScript.

See Runtime vs Fly.io and Runtime vs Freestyle.

Sources

Fly Sprites rates checked 23 September 2026; Freestyle rates checked 25 September 2026.

• Fly.io pricing, Sprites
• Freestyle pricing, Freestyle VM pricing and limits
• Runtime pricing

Facts on this page were checked on 25 September 2026.