Fly.io Machines vs Freestyle
Fly.io Machines are Firecracker microVMs for hosting your own apps in 17 regions, and you build any sandbox on top yourself. Freestyle sells full KVM VMs made for agents, with systemd, Docker, nested virtualization and coding agents ready, plus memory pause and live fork.
The companies and products
Fly.io Machines
Fly.io is an app hosting platform, and Machines are the microVMs underneath it that you can also start and stop through a REST API.
A Fly Machine boots your Docker image as a Firecracker microVM on Fly's own servers, in one of 17 regions. You pick a shared or performance CPU preset, attach at most one Volume for data that must last, and Fly Proxy can stop, suspend and wake Machines as traffic comes and goes. It is built for teams that host web apps and services worldwide; it is not a sandbox product, so this page compares the parts that overlap with agent work.
Freestyle
Freestyle sells full Linux virtual machines for AI agents, built for long running, complex tasks.
Each Freestyle VM is a KVM virtual machine with its own kernel, booted from an Ubuntu base snapshot with systemd, Docker and coding agent CLIs preinstalled. VMs can be paused with their memory, snapshotted while running, forked and woken by the next request, and every VM starts behind a default-deny firewall. It is built for teams that give each agent or each user its own machine, driven from a TypeScript SDK, a CLI or an API.
Which use cases each one fits
For each use case, Battleships prices every sandbox provider on the same workload and sorts them from the cheapest monthly bill up. “92nd cheapest of 367” means 91 of the other 366 providers run that workload, with every feature it needs, for less. “With limits” means the provider runs it but misses something, so it is listed after every full match. Open a use case for its whole ranking and what each provider misses.
| Use case and its workload | Fly.io Machines: price rank | Freestyle: price rank | boat: price rank |
|---|---|---|---|
| Software factory 100 at once · 4 vCPU / 8 GB · 2,200 sessions of 8 h a month Freestyle has systemd, Docker and /dev/kvm ready, while a Fly Machine resets its root disk on restart and has no nested virtualization; boat fits fully with faster measured CPUs. | 92nd of 367, with limits $836 a month | 241st of 367, with limits $3,311 a month | 3rd cheapest of 367 $634 a month |
| Always-on AI employees 50 machines 24/7 · 2 vCPU / 4 GB | 125th of 366, with limits $816 a month | 263rd of 366, with limits $4,195 a month | 5th cheapest of 366 $657 a month |
| Code interpreter bursts 100 at once · 1 vCPU / 2 GB · 200,000 sessions of 1 min a month Freestyle ranks 40th here, ahead of Fly at 75th, because its VMs pause with memory and wake on the next request. | 75th of 345, with limits $94 a month | 40th cheapest of 345 $482 a month | 186th of 345, with limits $2,000 a month |
| Sandboxes for your users 300 at once · 2 vCPU / 4 GB · 30,000 sessions of 23 min a month Freestyle fits fully and wakes a paused user VM on its next request; Fly creates about one Machine per second per app; boat ranks first. | 69th of 361, with limits $600 a month | 16th cheapest of 361 $1,358 a month | Cheapest of 361 $209 a month |
| RL rollouts 1,000 at once · 2 vCPU / 4 GB · 1,000,000 sessions of 3 min a month Fly ranks 48th and Freestyle 107th; Freestyle can snapshot a running VM with its memory and boot copies, which suits rollouts that branch. | 48th of 360, with limits $2,838 a month | 107th of 360, with limits $6,600 a month | 34th of 360, with limits $2,000 a month |
| Agent evals 250 at once · 4 vCPU / 8 GB · 15,000 sessions of 20 min a month | 117th of 364, with limits $457 a month | 53rd cheapest of 364 $1,046 a month | 10th cheapest of 364 $200 a month |
| CI runners 40 at once · 8 vCPU / 16 GB · 6,000 sessions of 12 min a month Busy CI jobs drain a shared Fly vCPU's burst balance, and Freestyle's docs send sustained heavy CPU work elsewhere; boat ranks 4th. | 152nd of 377, with limits $288 a month | 168th of 377, with limits $625 a month | 4th cheapest of 377 $86 a month |
| 24/7 dev boxes 1 machine 24/7 · 4 vCPU / 8 GB Freestyle fits a 24/7 dev box fully with its whole disk kept, while Fly keeps only what is on one Volume. | 118th of 368, with limits $53 a month | 98th cheapest of 368 $151 a month | 18th cheapest of 368 $26 a month |
| Computer-use agents 50 at once · 4 vCPU / 8 GB · 20,000 sessions of 15 min a month Neither ships a desktop: on Fly you build it into your image, on Freestyle you follow guides to install GNOME or Xvfb and VNC; boat streams one at 60fps. | 95th of 369, with limits $173 a month | 234th of 369, with limits $940 a month | 6th cheapest of 369 $200 a month |
| Browser-use agents 50 at once · 2 vCPU / 4 GB · 30,000 sessions of 10 min a month | 160th of 367, with limits $90 a month | 257th of 367, with limits $482 a month | 7th cheapest of 367 $200 a month |
| Scraping & bots (startup scale) 50 at once · 1 vCPU / 2 GB · 100,000 sessions of 3 min a month | 161st of 346, with limits $67 a month | 278th of 346, with limits $482 a month | 6th cheapest of 346 $90 a month |
| Mass scraping & bots (undetectable) 1,000 at once · 1 vCPU / 2 GB · 3,000,000 sessions of 2 min a month Fly ranks 44th, the best of the three, since it can spread scrapers across 17 regions and bill only the seconds they run. | 44th of 338, with limits $1,232 a month | 183rd of 338, with limits $6,560 a month | 71st of 338, with limits $1,800 a month |
| Parallel red teaming 200 at once · 2 vCPU / 4 GB · 5,000 sessions of 30 min a month | 118th of 360, with limits $63 a month | 272nd of 360, with limits $482 a month | 2nd cheapest of 360 $200 a month |
| GPU eval jobs 10 at once · 8 vCPU / 32 GB · 500 sessions of 30 min a month | Can't run it | Can't run it | Can't run it |
| macOS agents 5 at once · 4 vCPU / 8 GB · 1,000 sessions of 20 min a month | Can't run it | Can't run it | Can't run it |
Key features
| Feature | Fly.io Machines | Freestyle | boat |
|---|---|---|---|
| Kind of product | App hosting platform; Machines are its VM building block with a REST API | Full Linux VMs sold for AI agents | Agent sandbox: a full VM per agent, ready to use |
| Isolation | Firecracker microVM with its own kernel | Full KVM VM with its own kernel on bare metal servers | Full VM with its own kernel on dedicated AMD Ryzen 9 9950X hosts |
| Docker, systemd and nested virtualization | Root and Docker you install yourself; Fly's own init, no systemd; no /dev/kvm | systemd is pid 1, Docker runs from boot, full KVM support | Docker, root, systemd and /dev/kvm on every machine |
| CPU benchmark (4 vCPU / 8 GB) | Not measured; shared vCPUs guarantee 6.25% of a core, performance vCPUs the full core | 9.64 runs/s | 26.69 runs/s |
| Files after a stop | Root file system is ephemeral; lasting data goes on one Volume, billed for its full size | Whole disk kept; a paused VM bills for its storage | Whole disk kept, saved every minute and on stop; a stopped sandbox costs nothing |
| Pause with memory | Suspend keeps memory for Machines up to 2GB; dropped on deploy or host move | Pause saves memory and disk; the same processes resume | Resume boots again from disk (no memory snapshots) |
| Fork | Clone copies a Machine's config; a cloned Volume starts empty | Clone a running VM without pausing it; snapshots capture memory and disk | Fork a running sandbox with its disk |
| Wake on request | Fly Proxy stops or suspends idle Machines and wakes them on traffic | A VM paused by idle timeout resumes on the next traffic | No; you start a stopped sandbox through the API |
| Coding agents | None built in; you install and run them yourself | claude, codex, opencode and openclaw preinstalled, driven through exec or a terminal | Seven agents preinstalled, with a prompt, steer and events API to drive them from outside |
| Desktop, browser and computer use | None built in; you add them to your own image | Guides to install GNOME or Xvfb, VNC and Chromium yourself | 60fps Linux desktop, Chromium and computer use built in, embeddable stream |
| Keeping keys out of the sandbox | Secrets arrive as environment variables; open-source tokenizer proxy you deploy yourself | Credentials injected at the edge for HTTPS headers, Postgres and S3 | Credentials proxy for model providers and any HTTPS API; switch to another account when credits run out |
| Outbound rules | Network policies allow chosen ports and protocols and deny the rest | Default-deny firewall with allow rules by IP, VM, VPC or exact domain | Open internet on every plan; no provider-side allowlist |
| Biggest machine | Pick a shared or performance CPU preset | Up to 32 vCPU / 64 GiB on Pro, 64 / 128 with custom limits | Up to 16 vCPU / 32 GB on the $100 plan and above |
| Regions | 17 regions on six continents | Not listed; the docs name a San Jose, US data center | EU only: Germany, Finland, France, with EU data residency |
Every feature Battleships tracks (43)
| Feature | Fly.io Machines | Freestyle | boat |
|---|---|---|---|
| Full VM (own kernel) | Yes | Yes | Yes |
| Docker inside | Yes | Yes | Yes |
| Nested virtualization | No | Yes | Yes |
| Root | Yes | Yes | Yes |
| Systemd | No | Yes | Yes |
| Desktop GUI | No | No | Yes |
| Browser | No | No | Yes |
| Computer-use API | No | No | Yes |
| SSH | Yes | Yes | Yes |
| Persistent disk | Yes | Yes | Yes |
| Pause/resume | Yes | Yes | Yes |
| Automatic snapshots | Yes | Yes | Yes |
| Fork/clone | Yes | Yes | Yes |
| Live fork (no pause) | Yes | Yes | Yes |
| Memory fork | No | Yes | No |
| Custom image (Docker or snapshot) | Yes | Yes | Yes |
| ≥24 h sessions | Yes | Yes | Yes |
| Idle auto-stop | Yes | Yes | No |
| Wake on request | Yes | Yes | No |
| HTTPS preview URLs | Yes | Yes | Yes |
| Raw TCP inbound | Yes | Yes | Yes |
| Public IPv4 | Yes | No | No |
| Egress allowlist | Yes | Yes | No |
| Secret proxy | No | Yes | Yes |
| Secret proxy for any API | No | Yes | Yes |
| Preinstalled agents | No | Yes | Yes |
| Agent harness API | No | No | Yes |
| MCP server | Yes | No | No |
| GPU | No | Yes | No |
| Windows | No | No | No |
| Arm64 | No | No | No |
| Self-hosting | No | No | No |
| BYOC | No | No | No |
| Open source | Yes | No | No |
| Scoped API keys | Not published | Yes | Yes |
| Spend limits | No | Not published | Yes |
| Usage per sandbox (API) | No | No | Yes |
| Audit logs | Not published | Yes | No |
| SSO | No | Yes | No |
| SOC 2 | Yes | Not published | No |
| HIPAA | Yes | Not published | No |
| EU data residency | Yes | No | Yes |
| Zero data retention | Not published | Not published | Yes |
Performance
On the hpc-sandbox-benchmarks Node.js build-and-test loop at 4 vCPU / 8 GB, boat did 26.69 runs per second and Freestyle did 9.64, so boat did about 2.8 times the CPU work. Fly.io Machines have no comparable measurement, and their speed would depend on whether you pick shared vCPUs, which guarantee 6.25% of a core, or performance vCPUs.
Node.js build-and-test loop at 4 vCPU / 8 GB, higher is better. Measured with the open hpc-sandbox-benchmarks suite. Fly.io Machines has no published run in this suite yet, so there is no like-for-like number to compare.
Pricing in five scenarios
Each bill is priced from the providers' public price lists by the open Battleships engine, with the cheapest plan that runs the scenario.
| Scenario | Fly.io Machines, a month | Freestyle, a month | boat, a month |
|---|---|---|---|
| One coding agent, workdays 4 vCPU / 8 GB, 50 GB disk, 8 hours a day, 22 days a month, files kept between days | $15 · Pay As You Go · with limits | $27 · Free | $20 · $20/mo |
| One agent that never stops 4 vCPU / 8 GB, 50 GB disk, running 24/7 all month | $36 · Pay As You Go · with limits | $159 · Free | $26 · $20/mo |
| 50 agents in parallel 50 machines of 4 vCPU / 8 GB at once, 8-hour sessions, 1,100 sessions a month, Docker inside | $487 · Pay As You Go · with limits | $2,139 · Pro | $317 · $20/mo × 3 seats |
| Sandboxes for your users 2 vCPU / 4 GB, 30,000 sessions of 10 minutes a month, up to 300 at once | $110 · Pay As You Go · with limits | $581 · Pro | $200 · $100/mo × 2 seats |
| 1,000 short jobs at once 2 vCPU / 4 GB, 1,000 at once, 3 minutes each, 200,000 jobs a month | $232 · Pay As You Go · with limits | $1,305 · Pro · with limits | $2,000 · $2000/mo · with limits |
Fly.io Machines: Fly bills each Machine per second while it runs, by CPU preset and memory, with no plan fee; Volumes bill for their full size all month. The figures here use Fly's lowest rate: shared vCPUs bought in 1-year reservation blocks.
Freestyle: Freestyle bills per second for the vCPU, RAM and disk allocated to a VM, busy or idle, after monthly allowances. Free stops when the allowances run out; Hobby and Pro have a $50 or $500 monthly minimum that counts as usage.
Freestyle: Plans start at $20 a month and the whole fee is usage credit, spent per second while a sandbox runs. A stopped sandbox costs nothing and keeps its disk.
Limits in those scenarios
Fly is marked a compromise in every scenario because its lowest figures need a 1-year reservation and use shared vCPUs that throttle above 6.25% of each core. Freestyle fits the first four scenarios, but 50 agents need Pro, and Pro's cap of 400 concurrent VMs is why it does not fit 1,000 short jobs at once. Freestyle has no idle timeout by default, so a VM bills until you pause it. boat does not fit that burst either: its starts per minute and per day are capped, so the jobs get queued.
| Scenario | Fly.io Machines | Freestyle | boat |
|---|---|---|---|
| One coding agent, workdays |
| None that bite | None that bite |
| One agent that never stops |
| None that bite | None that bite |
| 50 agents in parallel |
| None that bite | None that bite |
| Sandboxes for your users |
| None that bite | None that bite |
| 1,000 short jobs at once |
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Which one should you use?
Use Fly.io Machines when
you host apps or light services that must run near users on several continents, sleep between requests and wake on traffic.
- 17 regions worldwide. Useful when agents or users sit far apart: Fly runs Machines in 17 regions, from the US to Sydney and Johannesburg.
- A full app platform around each Machine. Useful if you also host the product: private networking, Anycast IPs, custom domains and port-level network policies come built in.
- No plan fee. Useful for light or bursty work: Fly bills each Machine per second while it runs, with no monthly minimum.
Use Freestyle when
you want a ready agent VM that pauses with its memory, forks while running, starts behind a default-deny firewall or needs more than 16 vCPU.
- Built as an agent VM. Useful if you want a ready machine: systemd, Docker, nested virtualization and four coding agent CLIs come in the base image.
- Memory pause and live fork. Useful for VMs that sleep and branch: pause keeps the running processes, and you can clone a VM while it runs.
- Default-deny network and big machines. Useful for locked-down or heavy jobs: each VM starts with no network access, and Pro VMs go up to 32 vCPU.
Where boat fits
If what you are really running is coding agents that work for hours, look at boat too. Fly makes you build the sandbox yourself, and Freestyle gives you the VM but not the desktop or a way to drive the agents. boat ships both on faster measured CPUs, with a disk that is kept for free when the machine stops.
Faster CPUs for builds and tests
On the same Node.js build-and-test benchmark at 4 vCPU / 8 GB, boat did 26.69 runs per second and Freestyle 9.64. Fly was not measured, and its cheap shared vCPUs throttle once a long build drains the burst balance.
A disk that is kept, and free when stopped
An agent leaves tools and caches all over its disk. Fly keeps only one Volume and resets the rest on restart, and Freestyle bills a paused VM for storage. boat keeps the whole disk, saved every minute, and a stopped machine costs nothing.
Desktop and agents you drive from outside
Neither ships a desktop: on Fly you build it into your image, on Freestyle you install GNOME or Xvfb and VNC. boat streams a 60fps desktop with computer use, and an API prompts and steers the agents inside.
Use boat when your agents do real work for hours: builds, tests, Docker and emulators on fast CPUs, with a desktop, a kept disk and an API to drive the agents inside from outside. Compare it one to one: boat vs Fly.io Machines and boat vs Freestyle.
Questions people ask
Is Fly.io Machines cheaper than Freestyle?
On paper, yes. One agent running all month is $36 on Fly and $159 on Freestyle, and 50 agents in parallel are $487 against $2,139. Fly's figures use shared vCPUs on a 1-year reservation, which throttle above 6.25% of a core; boat is $26 and $317 for the same two.
Which is faster, Fly.io Machines or Freestyle?
Freestyle did 9.64 runs per second on the hpc-sandbox-benchmarks CPU test at 4 vCPU / 8 GB, and Fly was not measured. Fly's shared vCPUs guarantee only 6.25% of a core, so sustained builds depend on the CPU class you pick. boat did 26.69 runs per second on the same test.
Can Fly.io Machines and Freestyle run Docker?
Both can. On Fly you install Docker yourself in your image, and there is no systemd or /dev/kvm, so nested VMs and Android emulators do not work. Freestyle runs Docker from boot with systemd and full KVM support, like boat.
Do they keep my files when a VM stops?
Freestyle keeps the whole disk and bills it while paused. A Fly Machine's root file system is ephemeral, so only what sits on its one Volume lasts. boat keeps the whole disk, saved every minute and on stop, at no cost while stopped.
Can either one pause with memory?
Both can. Fly suspends Machines up to 2GB of memory and drops the snapshot on deploy or host move, while Freestyle pauses a VM with its memory and disk and can clone it while it runs. boat keeps the disk but boots again on resume.
Where do they run?
Fly runs Machines in 17 regions on six continents. Freestyle does not list regions; its docs name a data center in San Jose, US. boat runs only in the EU, in Germany, Finland and France.
Try boat
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