Which is better, Fly Sprites or Freestyle?
It depends on how much memory the job holds and how you fork it. If your agent mostly waits on model replies, Runtime is the cheapest here: $0.64 for 1,000 one-minute runs, against $2.40 on Sprites and $2.25 on Freestyle, because it pairs measured CPU with a lower memory rate. Pick Fly Sprites for a personal machine with a 100 GB disk that costs little while asleep. Pick Freestyle for VMs of up to 32 vCPUs on Pro, or for forks taken without a pause.
At a glance
| Fly Sprites | Freestyle | Runtime | |
|---|---|---|---|
| Isolation | Firecracker microVM | Full Linux virtual machines | Firecracker microVM, own kernel |
| CPU | $0.0385 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 | $0.021875 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 meter it, but their memory rate is over half as much again as 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:
- CPU
- 1,000 × 20 s / 3,600 × $0.0385
- $0.21
- Memory
- 1,000 × 90 s / 3,600 × 4 × $0.021875
- $2.19
- 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
- CPU
- 1,000 × 20 s / 3,600 × $0.025
- $0.14
- Memory
- 1,000 × 60 s / 3,600 × 4 × $0.0075
- $0.50
If both CPUs were busy for the whole minute, the job would cost $3.47 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 costs little while asleep.
- Freestyle for VMs of up to 32 vCPUs on Pro, or forks with no pause.
- 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.
Runtime Cloud
Runtime costs 73% less than Sprites and 72% less than Freestyle for an agent that waits. 1,000 one-minute runs on 2 vCPU and 4 GiB, with 20 CPU-seconds each: $2.40 on Fly Sprites, $2.25 on Freestyle, $0.64 on Runtime.
A paused Runtime sandbox keeps its memory, and there is no plan fee. Run npx withruntime login to start free, and use the migration guide for code you already have.
Sources
Fly.io prices checked 25 October 2026.
Fly Sprites rates checked 25 October 2026; Freestyle rates checked 25 October 2026.
Facts on this page were checked on 26 October 2026.