Fly.io Machines vs Instabox

Fly.io Machines are microVMs for hosting your own apps in 17 regions, and you build the agent setup yourself. Instabox gives each AI agent its own Linux machine with Docker and a desktop, but it is an invite-only beta that launched on 2026-10-14, with one machine size and 5 machines per account.

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.

Kind of product: App hosting platform; Machines are its VM building block with a REST API
Isolation: Firecracker microVMs with hardware virtualization, on Fly's own servers
Regions: 17 regions in North America, Europe, Asia, Oceania, South America and Africa
CPU classes: Shared vCPUs guarantee 6.25% of each core with a burst balance; performance vCPUs get the full core
Storage: Root file system is ephemeral; one Volume of up to 500GB per Machine for lasting data
Free trial: 2 Machine hours or 7 days, up to 10 Machines of 2 vCPU / 4GB that stop after 5 minutes
Compliance: Lists SOC 2 Type II; a HIPAA package with a pre-signed BAA is sold as an add-on

Instabox

Instabox, made by InsForge, gives each AI agent its own Linux computer in the cloud. It launched on 2026-10-14 as an invite-only beta.

Each Instabox machine is a Firecracker microVM with its own kernel, root and Docker, started from one of four templates (agent-browser, universal, herdr or orca) or from your own snapshot. Every machine is 4 vCPU / 8 GiB with 20 GB of storage, and you drive it from a CLI, a TypeScript SDK or an HTTP API, with SSH, mosh, public port URLs and a desktop for computer use. It is aimed at developers who want a cloud box for a coding agent.

Isolation: Firecracker microVM per machine
Machine size: 4 vCPUs and 8 GiB of memory, the same for every machine; 20 GB storage
Machines per account: 5, in any state: paused and stopped ones count
Price: Free during the beta; no published price yet
Access: Invite-only beta; sign in with GitHub or Google
Regions: Not published; more regions are on the roadmap as an idea
Company: InsForge AI, Inc.

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	Instabox: price rank	boat: price rank
Software factory 100 at once · 4 vCPU / 8 GB · 2,200 sessions of 8 h a month A software factory needs many set-up machines: Fly's root disk resets on restart, Instabox forks only stopped machines and caps you at 5, and boat forks a running sandbox.	92nd of 367, with limits $836 a month	No published price	3rd cheapest of 367 $634 a month
Always-on AI employees 50 machines 24/7 · 2 vCPU / 4 GB An agent that runs for weeks keeps only its one Volume on Fly; Instabox keeps the machine but pauses it after 30 idle minutes unless you turn that off.	125th of 366, with limits $816 a month	No published price	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 Fly suits short bursts on paper, with per-second billing and no plan fee; Instabox has no published rate, so it is not ranked here.	75th of 345, with limits $94 a month	No published price	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 Instabox allows 5 machines per account, paused and stopped ones included, so it cannot give a sandbox to each of many users; Fly can, with pre-created Machines for sign-up waves.	69th of 361, with limits $600 a month	No published price	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	48th of 360, with limits $2,838 a month	No published price	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 Instabox's 5-machine cap limits how many evals run at once, and Fly's shared vCPUs throttle long busy runs.	117th of 364, with limits $457 a month	No published price	10th cheapest of 364 $200 a month
CI runners 40 at once · 8 vCPU / 16 GB · 6,000 sessions of 12 min a month CI jobs that build Android apps or VM images need /dev/kvm: Fly does not offer it, Instabox does not document it, and boat has it on every machine.	152nd of 377, with limits $288 a month	No published price	4th cheapest of 377 $86 a month
24/7 dev boxes 1 machine 24/7 · 4 vCPU / 8 GB	118th of 368, with limits $53 a month	No published price	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 Instabox has a Linux desktop with a browser and a screenshot and click API on one template; on Fly you build the desktop yourself; boat streams one at 60fps.	95th of 369, with limits $173 a month	No published price	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	No published price	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	No published price	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 can spread scrapers across 17 regions and pay only for the seconds they run; Instabox publishes no regions and allows 5 machines.	44th of 338, with limits $1,232 a month	No published price	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	No published price	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	No published price	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	No published price	Can't run it

Key features

Feature	Fly.io Machines	Instabox	boat
Kind of product	App hosting platform; Machines are its microVM building block with a REST API	Agent machines in an invite-only beta that launched on 2026-10-14	Agent sandbox: a full VM per agent, ready to use
Isolation	Firecracker microVM with its own kernel	Firecracker microVM with its own kernel and root	Full VM with its own kernel on dedicated AMD Ryzen 9 9950X hosts
Machine size and CPU	Shared or performance CPU presets; shared vCPUs guarantee 6.25% of a core plus bursts	One size for everyone: 4 vCPU / 8 GiB with 20 GB storage; CPU basis not published	Several sizes up to 16 vCPU / 32 GB, one CPU class with no baseline quota; 26.69 runs/s measured
Docker and systemd	Root and Docker you install yourself; Fly's own init, no systemd	Docker and Docker Compose run inside, with root; systemd not documented	Docker, root and systemd on every machine
Nested virtualization	No, /dev/kvm is not offered	Not documented	Yes, /dev/kvm for Android emulators and VMs
Files after a stop	Root file system is ephemeral; lasting data goes on one Volume, billed for its full size around the clock	Machine files are kept, within a 200 GB storage allowance shared with snapshots	The whole disk is kept, saved every minute and on stop; a stopped sandbox costs nothing
Snapshots and fork	Clone copies a Machine's config; a cloned Volume starts empty	Up to 10 snapshots saved by hand; fork copies a stopped machine only	Fork a running sandbox with its disk, plus named snapshots
Pause with memory	Suspend keeps memory for Machines up to 2GB; dropped on deploy or host move	Pause keeps memory and running programs; resume usually takes about a second	Resume reboots from disk (no memory snapshots)
Wake on request	Fly Proxy stops or suspends idle Machines and wakes them when a request arrives	No: port URLs go offline while a machine is paused, and a visit does not wake it	You start and stop machines through the API
Reaching the machine	Public HTTPS and TCP through Fly Proxy, Anycast IPs, custom domains, private network	HTTPS on up to 16 ports, open to anyone with the URL; SSH gateway with mosh	HTTPS on up to 50 ports, token-protected by default; raw TCP; SSH
Desktop and computer use	None built in; you add a desktop and browser to your own image	Linux desktop with a browser on one template, screenshot and click API; you bring the model	60fps Linux desktop with Chromium and a computer-use agent
Coding agents	None built in; you install and run agents yourself	Templates and saved agent sign-ins in snapshots; you run the agent yourself	Claude Code, Codex and more preinstalled, with a prompt, steer and events API
Keeping API keys out of the machine	Secrets arrive as environment variables; Fly's open-source tokenizer proxy can be deployed yourself	Vault writes your secrets into each machine as environment variables or files	Credentials proxy: real keys never enter the sandbox, for model providers and any HTTPS API
Regions	17 regions on six continents	Not published	EU only: Germany, Finland, France

Every feature Battleships tracks (43)

Feature	Fly.io Machines	Instabox	boat
Full VM (own kernel)	Yes	Yes	Yes
Docker inside	Yes	Yes	Yes
Nested virtualization	No	Not published	Yes
Root	Yes	Yes	Yes
Systemd	No	Not published	Yes
Desktop GUI	No	Yes	Yes
Browser	No	Yes	Yes
Computer-use API	No	Yes	Yes
SSH	Yes	Yes	Yes
Persistent disk	Yes	Yes	Yes
Pause/resume	Yes	Yes	Yes
Automatic snapshots	Yes	No	Yes
Fork/clone	Yes	Yes	Yes
Live fork (no pause)	Yes	No	Yes
Memory fork	No	No	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	No	No
HTTPS preview URLs	Yes	Yes	Yes
Raw TCP inbound	Yes	Not published	Yes
Public IPv4	Yes	No	No
Egress allowlist	Yes	Not published	No
Secret proxy	No	No	Yes
Secret proxy for any API	No	No	Yes
Preinstalled agents	No	Not published	Yes
Agent harness API	No	Not published	Yes
MCP server	Yes	Not published	No
GPU	No	No	No
Windows	No	No	No
Arm64	No	Not published	No
Self-hosting	No	Not published	No
BYOC	No	Not published	No
Open source	Yes	No	No
Scoped API keys	Not published	Yes	Yes
Spend limits	No	Not published	Yes
Usage per sandbox (API)	No	Yes	Yes
Audit logs	Not published	Not published	No
SSO	No	No	No
SOC 2	Yes	Not published	No
HIPAA	Yes	Not published	No
EU data residency	Yes	Not published	Yes
Zero data retention	Not published	Not published	Yes

Performance

Fly.io MachinesNot measured

InstaboxNot measured

boat26.69 runs/s

Neither Fly.io Machines nor Instabox has a comparable CPU measurement, so this page makes no speed claim between them. boat did 26.69 Node.js build-and-test runs per second at 4 vCPU / 8 GB in the public StarSling run. Fly's shared vCPUs guarantee 6.25% of a core plus bursts, and Instabox says a new machine's shell is ready in under a second, which has not been measured.

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 and Instabox have 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	Instabox, 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	No published price	$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	No published price	$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	No published price	$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	No published price	$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	No published price	$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 are billed for their full size all month. The figures here use shared vCPUs bought in 1-year reservation blocks for 40% off.

Instabox: Instabox is free during the beta, with 5 machines per account, and publishes no price yet, so no bill can be compared.

Instabox: Plans start at $20 a month, and the whole fee is usage credit spent per second while sandboxes run. A stopped sandbox costs nothing and keeps its disk.

Limits in those scenarios

Fly is a compromise in all five scenarios: its lowest figures need a 1-year reservation and use shared vCPUs that guarantee only 6.25% of each core, so long builds get throttled, and its API starts about one Machine per second per app. Instabox has no published rate, so no scenario can be priced, and its 5 machines per account, paused and stopped ones included, rule out the 50-agent and user-sandbox scenarios. On boat the 1,000-job burst is queued by its start limits, even on the $2,000 plan.

Scenario	Fly.io Machines	Instabox	boat
One coding agent, workdays	different kind of product: app platform 1-year commitment burstable CPU: 6.25% of each vCPU guaranteed, throttled above that	no published per-resource rate	None that bite
One agent that never stops	different kind of product: app platform 1-year commitment burstable CPU: 6.25% of each vCPU guaranteed, throttled above that	no published per-resource rate	None that bite
50 agents in parallel	different kind of product: app platform 1-year commitment burstable CPU: 6.25% of each vCPU guaranteed, throttled above that	no published per-resource rate	None that bite
Sandboxes for your users	different kind of product: app platform 1-year commitment burstable CPU: 6.25% of each vCPU guaranteed, throttled above that	no published per-resource rate	None that bite
1,000 short jobs at once	different kind of product: app platform 1-year commitment burstable CPU: 6.25% of each vCPU guaranteed, throttled above that	no published per-resource rate	max 2,400 starts/day (needs ~6,667) max 600 starts/hour (needs ~1,000) bursts above 90 starts/min are queued (a burst of 333 takes ~4 min to start)

Which one should you use?

Use Fly.io Machines when

you host web apps or light services that must run near users worldwide, sleep between requests and wake on traffic.

17 regions worldwide. Useful if your users are far apart: Fly runs Machines in 17 regions, from the US to Sydney and Johannesburg.
Wakes on traffic. Useful for services that sleep between requests: Fly Proxy starts an idle Machine again when a request arrives.
A full app platform with published terms. Useful if you host a whole product: per-second rates, private networking, Anycast IPs, custom domains and port-level network policies.

Use Instabox when

you want to try a few free 4 vCPU / 8 GiB agent machines during its beta, with memory pause, a desktop template and mosh.

Free during the beta. Useful for trying things out: every account can run 5 machines of 4 vCPU / 8 GiB for free while the beta lasts.
Pause with memory. Useful for agents that wait a lot: a paused machine keeps its memory and running programs and usually resumes in about a second.
Agent pieces ready to use. Useful if you do not want to build an image: Docker, a desktop template with a browser and an SSH gateway with mosh come built in.

Where boat fits

Fly gives you a fast microVM and leaves the agent setup to you, and Instabox gives you agent machines but only 5 of one size, with no published terms yet. If your agents run for hours, build and test, need emulators or a desktop, or you need more than five at once, boat gives each one a full VM with all of that built in.

A disk that keeps everything, forked while running

Fly's root disk resets on restart, so files must live on one Volume billed around the clock, and a clone gets an empty Volume. Instabox forks only stopped machines. boat saves the disk every minute and forks a running sandbox.

/dev/kvm, systemd and Docker ready

Fly offers no /dev/kvm and runs its own init instead of systemd, and Instabox does not document nested virtualization. Android emulators and nested VMs need /dev/kvm, which boat has on every machine.

Real keys never enter the sandbox

Fly passes secrets as environment variables unless you run its tokenizer proxy yourself, and Instabox writes vault secrets into the machine. Code an agent writes can read them. boat's credentials proxy keeps keys outside, for any HTTPS API.

Use boat when your agents do real work for hours on a full VM whose disk survives every stop, with /dev/kvm, a desktop, coding agents, a keys proxy and more than five machines at once. Compare it one to one: boat vs Fly.io Machines and boat vs Instabox.

Questions people ask

Is Fly.io Machines cheaper than Instabox?

It can't be compared yet. Instabox is free during the beta and publishes no price, so there is no bill to set against Fly's. Fly bills per second with no plan fee.

Which is faster, Fly.io Machines or Instabox?

Neither has a comparable CPU measurement, so there is no answer from data. Instabox says a new machine's shell is ready in under a second; that has not been measured. boat did 26.69 runs per second at 4 vCPU / 8 GB.

Can Fly.io Machines and Instabox run Docker?

Yes. Instabox runs Docker and Docker Compose inside its machines, and on Fly you install Docker in your Machine yourself. Fly does not offer /dev/kvm and Instabox does not document it, so nested VMs are not something to count on; boat has /dev/kvm.

Do they keep my files when a machine stops?

On Fly, only what sits on the one Volume a Machine can mount; the root file system is ephemeral. Instabox keeps machine files within a 200 GB storage allowance. boat keeps the whole disk and saves it every minute.

How many machines can I run?

Instabox allows 5 machines per account, and paused and stopped ones count. Fly's API starts about one Machine per second per app, so big bursts need pre-created Machines. boat has no session cap on paid plans.

Where do they run?

Fly runs Machines in 17 regions on six continents. Instabox does not publish its regions. boat runs only in the EU, in Germany, Finland and France.

Try boat

Install the CLI, then run boat new.

7-day free trial