Fly.io Machines vs Koyeb

Fly.io Machines are microVMs for hosting your own apps in 17 regions, and you build any sandbox on top yourself. Koyeb is a serverless cloud with a sandbox SDK, GPU instances and sandboxes that sleep when idle and wake on the next request.

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

Koyeb

Koyeb is a serverless cloud for apps, inference and sandboxes, and in February 2026 it agreed to join Mistral AI.

A Koyeb sandbox is a Koyeb service: a microVM started from any Docker image and driven from Python or JavaScript SDKs that run commands, read files and expose a port. It can scale to zero when idle and wake on the next request, and it can run on CPU or GPU instance types. It is built for teams that run AI agents or untrusted code next to apps they already host on Koyeb.

Isolation: MicroVM per instance
Company: Agreed to join Mistral AI (announced February 17, 2026); the platform keeps running and becomes part of Mistral Compute
Regions: Frankfurt, Paris, Washington D.C., AWS US East, Singapore, Tokyo, plus San Francisco in preview
CPU share: At least 0.25 dedicated vCPU per GB of memory, bursting to all cores
Your own infrastructure: Edge and on-premise deployments for Enterprise, on request
Compliance: ISO 27001 and SOC 2 listed on the Enterprise plan

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	Koyeb: price rank	boat: price rank
Software factory 100 at once · 4 vCPU / 8 GB · 2,200 sessions of 8 h a month Neither keeps a whole disk by default, so a software factory on Fly or Koyeb needs a volume per agent; boat ranks 3rd with the disk, Docker and /dev/kvm built in.	92nd of 367, with limits $836 a month	54th of 367, with limits $366 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	135th of 366, with limits $923 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 Koyeb ranks 4th for short code runs, with small instances that scale to zero and wake on request, well ahead of Fly at 75th.	75th of 345, with limits $94 a month	4th cheapest of 345 $66 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 boat ranks 1st and Koyeb ranks 6th; Koyeb wakes sleeping sandboxes on request, while Fly's API starts about one Machine per second per app.	69th of 361, with limits $600 a month	6th cheapest of 361 $495 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 for RL rollouts, far ahead of Koyeb at 237th; boat ranks 34th.	48th of 360, with limits $2,838 a month	237th of 360, with limits $1,631 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 Koyeb fits agent evals fully and ranks 19th, while Fly is a compromise because its cheapest shared vCPUs throttle under steady load.	117th of 364, with limits $457 a month	19th cheapest of 364 $429 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	152nd of 377, with limits $288 a month	142nd of 377, with limits $88 a month	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	217th of 368, with limits $37 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 Fly nor Koyeb ships a desktop, so computer-use agents need one built into your own image; boat streams a 60fps desktop with Chromium.	95th of 369, with limits $173 a month	81st of 369, with limits $123 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	172nd of 367, with limits $123 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	172nd of 346, with limits $89 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 here, ahead of Koyeb and boat, since it can spread scrapers across 17 regions and bill only the seconds they run.	44th of 338, with limits $1,232 a month	65th of 338, with limits $1,683 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	233rd of 360, with limits $299 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 Koyeb ranks 3rd for GPU eval jobs with instances up to H100 and H200; Fly has discontinued GPU Machines and boat has no GPUs.	Can't run it	3rd cheapest of 98 $628 a month	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	Koyeb	boat
Kind of product	App hosting platform; Machines are its VM building block with a REST API	Serverless cloud for apps, inference and sandboxes, with Python and JavaScript sandbox SDKs	Agent sandbox: a full VM per agent, ready to use
Isolation	Firecracker microVM with its own kernel	MicroVM per instance	Full VM with its own kernel on dedicated AMD Ryzen 9 9950X hosts
CPU	Shared vCPUs guarantee 6.25% of a core plus bursts; performance vCPUs get the full core at a higher rate	At least 0.25 dedicated vCPU per GB of memory, bursting to all cores; eco instances guarantee half of each vCPU	One CPU class on every plan, no burst balance; 26.69 runs/s on the CPU benchmark
Docker, systemd and nested virtualization	Root and Docker you install yourself; Fly's own init, no systemd; /dev/kvm not offered	Starts from any Docker image; nested virtualization not documented	Docker, root, systemd and /dev/kvm on every machine
Files after a stop	Root file system is ephemeral; one Volume of up to 500GB per Machine, billed for its full size around the clock	Local disk is lost on redeploy; volumes are in preview at 1 to 10 GB, in Frankfurt and Washington	The whole disk is kept, saved every minute and on stop; a stopped sandbox costs nothing
Sleep and wake	Fly Proxy stops or suspends idle Machines and wakes them on a request; suspend keeps memory up to 2GB	Scales to zero after at least 5 idle minutes and wakes on the next request; Light Sleep wakes in about 200 ms	Stop and start through the API; resume reboots from disk
Snapshots and fork	Clone copies a Machine's config; a cloned Volume starts empty	SDK snapshots of the filesystem, or with running processes, then new sandboxes from them (experimental)	Fork a running sandbox, disk included
Desktop and browser	None built in; you add a desktop and browser to your own image	No desktop or browser in the sandbox SDK	60fps Linux desktop with Chromium, computer use and browser control
Coding agents	None built in; you install and run agents yourself	Tutorials that run agents through the command API; an MCP server lets agents manage Koyeb	Claude Code, Codex and more preinstalled, with a prompt, steer and events API
Keeping keys out of the sandbox	Secrets arrive as environment variables; an open-source tokenizer proxy you deploy yourself	Secrets are set as environment variables inside the service	AI credentials proxy for model providers and any HTTPS API
Reaching the sandbox	Public HTTPS and TCP through Fly Proxy, Anycast IPs, custom domains, private network	One exposed HTTPS port at a time, plus an optional TCP proxy to one port; no dedicated IP	HTTPS URLs for up to 50 ports, token-protected; raw TCP; dedicated IPv4 or IPv6
Outbound rules	Network policies allow chosen ports and protocols and deny the rest	Block all outbound traffic, or allow only listed IPs and CIDRs	Open internet on every plan; no provider-side allowlist
GPUs	GPU Machines discontinued, unavailable from 2026-08-01	RTX 4000 SFF Ada up to H100, H200 and multi-GPU	No
Regions	17 regions on six continents	Frankfurt, Paris, Washington D.C., AWS US East, Singapore, Tokyo, San Francisco in preview	EU only: Germany, Finland, France

Every feature Battleships tracks (43)

Feature	Fly.io Machines	Koyeb	boat
Full VM (own kernel)	Yes	Yes	Yes
Docker inside	Yes	Yes	Yes
Nested virtualization	No	No	Yes
Root	Yes	Not published	Yes
Systemd	No	Not published	Yes
Desktop GUI	No	No	Yes
Browser	No	No	Yes
Computer-use API	No	No	Yes
SSH	Yes	No	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	Not published	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	No	Yes
Secret proxy for any API	No	No	Yes
Preinstalled agents	No	Yes	Yes
Agent harness API	No	No	Yes
MCP server	Yes	Yes	No
GPU	No	Yes	No
Windows	No	No	No
Arm64	No	No	No
Self-hosting	No	Yes	No
BYOC	No	Yes	No
Open source	Yes	No	No
Scoped API keys	Not published	Not published	Yes
Spend limits	No	No	Yes
Usage per sandbox (API)	No	No	Yes
Audit logs	Not published	Yes	No
SSO	No	Yes	No
SOC 2	Yes	Yes	No
HIPAA	Yes	No	No
EU data residency	Yes	Yes	Yes
Zero data retention	Not published	Not published	Yes

Performance

Fly.io MachinesNot measured

KoyebNot measured

boat26.69 runs/s

There is no comparable measurement for Fly.io Machines or Koyeb: neither was part of the StarSling run where boat did 26.69 Node.js build-and-test runs per second at 4 vCPU / 8 GB. On paper, Fly's shared vCPUs guarantee 6.25% of a core with a burst balance, while Koyeb guarantees at least 0.25 dedicated vCPU per GB of memory and bursts to all cores.

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 Koyeb 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	Koyeb, 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	$29 · Pro	$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	$57 · Pro	$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	$475 · 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	$329 · Scale	$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	$485 · Scale · 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 are billed for their full size all month. The figures here use shared vCPUs bought in 1-year reservation blocks for 40% off, the lowest rate Fly sells.

Koyeb: Koyeb bills each instance per second at a fixed price per instance type, and Deep Sleep costs nothing. Pro costs $29 a month with $10 of usage included and Scale $299 a month with $100 included; the rest of the fee is not credit.

Koyeb: 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 marked a compromise in every scenario: its lowest prices need a 1-year reservation, and its shared vCPUs guarantee only 6.25% of each core, so long builds drain the burst balance and get throttled. Koyeb's priced eco-xlarge shape has a 20 GiB disk with no published price for more, and its Pro plan allows 100 services. At 1,000 short jobs at once nobody fits as priced: Fly's API starts about one Machine per second per app, Koyeb's eco CPU guarantees only half of each vCPU, and boat queues starts above 90 a minute.

Scenario	Fly.io Machines	Koyeb	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	disk beyond 20 GiB: price unknown	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	disk beyond 20 GiB: price unknown	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	None that bite	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	None that bite	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	burstable CPU: 50% of each vCPU guaranteed, throttled above that	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 apps or light services that must run near users on many continents, sleep between requests and wake on traffic, or need large volumes.

17 regions worldwide. Useful if users sit in South America, Oceania or Africa: Fly runs Machines in 17 regions on six continents.
Bigger lasting volumes. Useful for agents with large data: a Fly Volume holds up to 500GB, while Koyeb's preview volumes stop at 10 GB.
A full app platform around each Machine. Useful if you host whole products: Anycast IPs, custom domains, private networking and port-level network policies come with every Machine.

Use Koyeb when

you want a ready sandbox SDK, need GPUs next to your sandboxes, or run sandboxes that sit idle and must wake on a request in the US or Asia.

GPUs in the same platform. Useful when an agent or eval needs a GPU: Koyeb runs instances from RTX 4000 cards up to H100 and H200.
A sandbox SDK out of the box. Useful if you want sandboxes without building the plumbing: Python and JavaScript SDKs run commands, read files and expose a port.
More guaranteed CPU. Useful for steady work: Koyeb guarantees at least 0.25 dedicated vCPU per GB of memory, against 6.25% of a core on Fly's shared vCPUs.

Where boat fits

If what you are really running is coding agents that work for hours, both Fly and Koyeb leave you building the sandbox yourself: the disk, the tools, the desktop and the agent harness. boat gives each agent a full VM that keeps its disk, with Docker, /dev/kvm, a desktop and coding agents ready. Pick Fly or Koyeb instead when you need regions outside Europe, GPUs or wake on request.

A disk that keeps everything, and forks

Fly's root file system is ephemeral and a Volume is billed for its full size even while stopped. Koyeb loses the local disk on redeploy, and its volumes are a 1 to 10 GB preview. boat keeps the whole disk and can fork a running sandbox.

A full VM with systemd and /dev/kvm

Neither Fly nor Koyeb offers /dev/kvm, so Android emulators and nested VMs have to run elsewhere, and Fly boots its own init instead of systemd. boat has root, systemd, Docker and /dev/kvm on every machine.

Agents, desktop and keys handled

On both, secrets reach the sandbox as environment variables an agent's code can read, and you build the desktop, browser and agent control yourself. boat ships a 60fps desktop, preinstalled coding agents you drive from outside, and a credentials proxy.

Use boat when your agents do real work for hours on a full VM that keeps its disk: builds, Docker, emulators, a desktop browser and preview servers, with coding agents and keys handled for you. Compare it one to one: boat vs Fly.io Machines and boat vs Koyeb.

Questions people ask

Is Fly.io Machines cheaper than Koyeb?

Often, if you accept a 1-year reservation and shared vCPUs that guarantee 6.25% of a core: one agent on workdays is $15 on Fly against $29 on Koyeb, and 300 user sandboxes are $110 against $329 a month. For 50 agents in parallel they are close, $487 against $475 a month, and boat is $317.

Which is faster, Fly.io Machines or Koyeb?

Neither has a comparable benchmark, so there is no measured answer. Koyeb guarantees more CPU on paper, at least 0.25 dedicated vCPU per GB of memory, while Fly's shared vCPUs guarantee 6.25% of a core; Fly's performance vCPUs get the full core at a higher rate.

Can I run Docker inside Fly.io Machines or Koyeb?

Both start from Docker images. On Fly you can install and run Docker inside a Machine yourself since you have root, but there is no /dev/kvm; Koyeb does not document nested virtualization. boat has Docker, systemd and /dev/kvm ready on every machine.

Do they keep my files when a machine stops?

Only on a volume. A Fly Machine's root file system is ephemeral, and one Volume of up to 500GB holds lasting data; Koyeb's local disk is lost on redeploy and its volumes are a 1 to 10 GB preview. boat keeps the whole disk and saves it every minute.

Do Fly.io Machines or Koyeb have GPUs?

Koyeb does, from an RTX 4000 SFF Ada up to H100 and H200, billed per second. Fly has discontinued GPU Machines, which are unavailable from 2026-08-01. boat is CPU only.

Where do they run?

Fly runs Machines in 17 regions on six continents. Koyeb runs in Frankfurt, Paris, Washington D.C., AWS US East, Singapore and Tokyo, with San Francisco in preview. boat runs only in the EU, in Germany, Finland and France.

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