Modal vs Instabox
Modal runs short-lived sandboxes inside a large AI compute platform, with GPUs, many regions and huge bursts of jobs. Instabox, which launched on 14 October 2026 as an invite-only beta, gives each agent its own Firecracker VM with Docker that can pause with its memory, in one size and up to 5 per account.
The companies and products
Modal
Modal is a serverless cloud for AI work: inference, training, batch jobs and sandboxed code, all driven from Python, TypeScript or Go code.
Modal Sandboxes are containers you create from code, run commands in, and then terminate. By default they run under gVisor, a user-space kernel from Google; since October 2026 you can also pick a VM runtime with its own Linux kernel for Docker and FUSE (Battleships tracks that as a separate card, Modal VM Sandboxes). It suits teams that already run models on Modal and want short-lived, scalable code execution next to their GPUs.
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
- Machines per account
- 5, in any state: paused and stopped ones count
- 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. “19th cheapest of 345” means 18 of the other 344 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 | Modal: 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 Software factories need Docker, a desktop and a disk that lasts: Modal resets its root disk when a sandbox ends, Instabox forks only stopped machines, and boat forks a running sandbox. | Can't run it | No published price | 3rd cheapest of 367 $634 a month |
| Always-on AI employees 50 machines 24/7 · 2 vCPU / 4 GB An always-on agent hits Modal's 24-hour sandbox limit; Instabox documents no maximum run time but pauses after 30 idle minutes unless you turn that off, and boat has no session cap on paid plans. | 196th of 366, with limits $1,924 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 For huge numbers of short code runs, Modal's fast starts and high concurrency fit well; Instabox's 5 machines per account and 4 exec calls at once do not. | 19th cheapest of 345 $181 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 counts paused and stopped machines toward its 5 per account, so it cannot give a sandbox to each of many users; Modal and boat both fit this case. | 11th cheapest of 361 $811 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 RL rollouts launch many short sandboxes at once, which is what Modal is built for and what Instabox's 5-machine cap rules out today. | 5th cheapest of 360 $19,038 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 | 59th cheapest of 364 $1,244 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 Docker images run on Instabox and on every boat sandbox, but on Modal only with the VM runtime; builds that need /dev/kvm run on boat. | 126th cheapest of 377 $1,793 a month | No published price | 4th cheapest of 377 $86 a month |
| 24/7 dev boxes 1 machine 24/7 · 4 vCPU / 8 GB | 138th of 368, with limits $23 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 boat ships a 60fps desktop with Chromium and a computer-use agent, Instabox has a desktop template with a screenshot and click API, and on Modal you set up VNC yourself. | 98th of 369, with limits $183 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 | 177th of 367, with limits $136 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 | 267th of 346, with limits $394 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 | 223rd of 338, with limits $8,795 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 | Can't run it | 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 Modal has GPUs from T4 to B300, and neither Instabox nor boat has GPUs, so Modal is the pick for GPU jobs. | 19th cheapest of 98 $1,187 a month | 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 | Modal | Instabox | boat |
|---|---|---|---|
| Isolation | gVisor user-space kernel by default; a VM runtime with its own kernel is available | Firecracker microVM with its own kernel and root | Full VM with its own kernel on dedicated AMD Ryzen 9 9950X hosts |
| Docker inside | Only with the VM runtime | Docker and Docker Compose run inside | Docker and Compose run inside, with root and systemd |
| Nested virtualization | VM runtime only, on Team and Enterprise plans, on request | Not documented | Yes, /dev/kvm for Android emulators and VMs |
| Machine sizes | You request CPU and memory per sandbox; the maximum is not published | One size for everyone: 4 vCPU / 8 GiB with 20 GB storage; other sizes are refused | Several sizes, up to 8 vCPU / 16 GB on the $20 plan and 16 vCPU / 32 GB on $100 and above |
| Longest session | 24 hours (default 5 minutes) | No maximum documented; pauses after 30 idle minutes by default, which you can change or turn off | No cap on paid plans (default TTL 1 h, changeable) |
| Stop, pause and resume | No paused state; a finished sandbox is gone, only Volumes keep files | Pause keeps memory and running programs; resume usually takes about a second | Stop for free with the whole disk kept; start boots the machine again |
| Fork and snapshots | Snapshot the filesystem into an image and boot new sandboxes from it; memory snapshots in alpha end the sandbox | Fork copies a stopped machine only; up to 10 snapshots, and saving stops a running machine first unless the server allows a live save | Fork a running sandbox without stopping it; disk saved every minute and on stop |
| GPUs | T4 to B300; 10 at once on Starter, 50 on Team | None | None |
| Desktop and computer use | Not offered; an example shows how to set up VNC yourself | Linux desktop with a browser on one template, screenshot and click API, shareable view or control links; you bring the model | 60fps Linux desktop with Chromium and a computer-use agent built in |
| Public ports | Encrypted and raw TCP tunnels, connect tokens, inbound IP allowlist | HTTPS on up to 16 ports, open to anyone with the URL; offline while the machine is paused | HTTPS on up to 50 ports, token-protected by default, plus raw TCP |
| SSH | Supported | Gateway with short-lived certificates, paste-anywhere SSH tokens and mosh | SSH into every sandbox |
| Outbound network rules | Block all, IP-range allowlist, domain allowlist (beta) | Not documented | No provider-side allowlist |
| Coding agents and API keys | Examples only; secrets are environment variables, or you run your own proxy in a sidecar | Templates and saved agent sign-ins in snapshots; a vault writes your secrets into each machine as environment variables or files | Seven agents preinstalled, driven from outside through one API; a credentials proxy keeps real keys out of the sandbox for any HTTPS API |
| Regions | US, EU and Asia-Pacific; pinning a region costs 1.15x to 1.75x | Not published | EU only: Germany, Finland, France |
Every feature Battleships tracks (43)
| Feature | Modal | Instabox | boat |
|---|---|---|---|
| Full VM (own kernel) | No | Yes | Yes |
| Docker inside | No | Yes | Yes |
| Nested virtualization | No | Not published | Yes |
| Root | Yes | Yes | Yes |
| Systemd | Yes | 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 | No | Yes | Yes |
| Automatic snapshots | No | No | Yes |
| Fork/clone | Yes | Yes | Yes |
| Live fork (no pause) | No | No | Yes |
| Memory fork | Yes | 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 | No | No | No |
| HTTPS preview URLs | Yes | Yes | Yes |
| Raw TCP inbound | Yes | Not published | Yes |
| Public IPv4 | No | 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 | No | Not published | No |
| GPU | Yes | No | No |
| Windows | No | No | No |
| Arm64 | No | Not published | No |
| Self-hosting | No | Not published | No |
| BYOC | No | Not published | No |
| Open source | No | No | No |
| Scoped API keys | Not published | Yes | Yes |
| Spend limits | Not published | Not published | Yes |
| Usage per sandbox (API) | Not published | Yes | Yes |
| Audit logs | Yes | Not published | No |
| SSO | Yes | 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
In the hpc-sandbox-benchmarks Node.js build-and-test loop at 4 vCPU / 8 GB, run on 29 September 2026, boat finished 26.69 runs per second and Modal's default gVisor sandbox 12.79, so boat did about twice the work. Instabox has no comparable measurement, so this page makes no speed claim for it. Instabox says a new machine's shell is ready in under a second; that 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. Modal measured on: Sandbox (gVisor), request = size, any region. Instabox 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 | Modal, 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 · Starter · 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 | $178 · Starter · 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 | $2,229 · Starter · 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 | $792 · Team | 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 | $3,193 · Team · with limits | No published price | $2,000 · $2000/mo · with limits |
Modal: Modal bills by the second for whichever is higher, the CPU and memory you request or what you use, and an idle sandbox pays until it is terminated. Starter is free with $30 of monthly credit, and Team is $250 a month with $100 of credit.
Instabox: Instabox is free during the beta, with 5 machines per account, and publishes no price yet. Its pricing page says it is free until they figure it out, so no bill can be compared with Modal's or boat's.
Instabox: boat charges one hourly rate per machine size, by the second, only while the sandbox runs. Plans start at $20 a month and the whole fee becomes usage credit; a stopped sandbox costs nothing.
Limits in those scenarios
On Modal, a sandbox lives at most 24 hours and its root disk is wiped when it ends, so the workday, always-on and fleet scenarios keep only files in a Volume, and the 50-agent fleet needs Docker, which the default sandbox lacks. Instabox publishes no rate, so no scenario can be priced, and its 5 machines per account, paused and stopped ones included, rule out the fleet, user-sandbox and burst scenarios today. On boat, the limit that bites is start speed: a burst of 1,000 short jobs exceeds the starts per hour and per day of even the $2,000 plan.
| Scenario | Modal | Instabox | boat |
|---|---|---|---|
| One coding agent, workdays |
|
| None that bite |
| One agent that never stops |
|
| None that bite |
| 50 agents in parallel |
|
| None that bite |
| Sandboxes for your users | None that bite |
| None that bite |
| 1,000 short jobs at once |
|
|
|
Which one should you use?
Use Modal when
your sandboxes need GPUs, must run outside Europe, or are huge bursts of short jobs that finish in minutes.
- GPUs next to your sandboxes. Useful if your agent trains or runs models: Modal rents GPUs from T4 to B300 on the same platform as its sandboxes.
- Regions and outbound rules. Modal runs in the US, EU and Asia-Pacific, and can block a sandbox's outbound traffic or allow only chosen domains.
- Very large bursts of short jobs. Useful for evals and RL rollouts: Modal runs up to 5,000 containers at once on its Team plan.
Use Instabox when
you want to try a few free 4 vCPU / 8 GiB agent machines during its invite-only beta, with memory pause and mosh.
- Free during the beta. While the invite-only beta lasts, every account can run 5 machines of 4 vCPU / 8 GiB for free.
- Pause with memory. A paused machine keeps its memory and running programs and usually resumes in about a second.
- SSH gateway with mosh. Its SSH gateway relays mosh and gives paste-anywhere SSH tokens, so a session survives sleep and network changes.
Where boat fits
If what you are really running is coding agents that work for hours, look at boat. Modal ends a sandbox within 24 hours and Instabox gives you five machines of one size, while boat gives each agent a full VM that keeps its disk, forks while running and has no session cap on paid plans.
Work that lasts and branches
A Modal sandbox ends within 24 hours and loses everything outside a Volume. Instabox keeps the disk, but forking or saving a snapshot stops the running machine. boat saves the disk every minute and forks a running sandbox.
Docker, /dev/kvm and room to grow
On Modal, Docker needs the VM runtime and /dev/kvm is on request for Team and Enterprise. Instabox does not document nested virtualization and has one 4 vCPU / 8 GiB size. boat has Docker, systemd, /dev/kvm and sizes up to 16 vCPU / 32 GB.
Desktop, agents and keys handled
Modal has no desktop and puts secrets in environment variables unless you run a sidecar proxy. Instabox writes secrets into the machine and leaves the agent to you. boat has a 60fps desktop, agents you drive from outside and a credentials proxy.
Use boat when your agents work for hours or days and need Docker, /dev/kvm, a desktop, forks of running work and more than five machines, on terms published today. Compare it one to one: boat vs Modal and boat vs Instabox.
Questions people ask
Is Modal cheaper than Instabox?
It can't be compared yet. Instabox is free during its beta, with 5 machines per account, and publishes no price, so there is no bill to set against Modal's. Modal's prices for each scenario are in the table above.
Which is faster, Modal or Instabox?
Only Modal has been measured: its default sandbox did 12.79 runs per second at 4 vCPU / 8 GB, against 26.69 for boat. Instabox's CPU speed has not been benchmarked, and its claim of a shell in under a second has not been measured.
Can Modal and Instabox run Docker?
Instabox runs Docker and Docker Compose in every machine. Modal runs Docker only with its VM runtime, not in the default gVisor sandbox. Every boat sandbox runs Docker with no extra setting.
How long can a sandbox run on Modal and on Instabox?
A Modal sandbox runs 5 minutes by default and 24 hours at most. Instabox documents no maximum, but a new machine pauses after 30 idle minutes unless you change that. boat has no session cap on paid plans.
Does Instabox start a machine in under a second?
Instabox says you are in a new machine's shell in under a second. Its docs say a paused machine usually resumes in about a second. Neither has been measured here.
Do Modal or Instabox have GPUs?
Modal has GPUs from T4 to B300, 10 at once on Starter and 50 on Team. Instabox has none, and neither does boat, so for GPU work Modal is the fit.
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