Cloudflare Sandbox vs Instabox
Both run each sandbox in its own Firecracker microVM. Cloudflare Sandbox is a container inside the Workers platform that sleeps when idle and starts again from a fresh disk, while Instabox is a new invite-only beta that gives each agent one fixed-size Linux machine it can pause with its memory.
The companies and products
Cloudflare Sandbox
Cloudflare Sandbox SDK runs untrusted or AI-generated code in Linux containers on Cloudflare's network, driven from a Cloudflare Worker.
Each sandbox is a Cloudflare Container backed by a Durable Object, and each container runs in its own Firecracker microVM with its own kernel and network. You build a linux/amd64 image, pick an instance type of up to 4 vCPU and 12 GiB, and reach the sandbox through your own Worker. It suits teams already on Workers who want short-lived sandboxes that sleep when idle; for code that only calls known methods, Cloudflare also offers Dynamic Workers, which run JavaScript in V8 isolates.
- Largest instance
- 4 vCPU, 12 GiB memory, 20 GB disk (defaults, can be raised)
- Account limits
- 1,500 vCPU, 6 TiB memory and 30 TB disk running at once
- Compliance
- Cloudflare holds a SOC 2 Type II report
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. “13th cheapest of 345” means 12 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 | Cloudflare Sandbox: 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 repos and installed tools to stay put; Cloudflare starts from a fresh disk after sleep and Instabox forks only stopped machines, while boat keeps the disk and forks a running sandbox. | 162nd of 367, with limits $1,543 a month | No published price | 3rd cheapest of 367 $634 a month |
| Always-on AI employees 50 machines 24/7 · 2 vCPU / 4 GB Always-on assistants need their files to stay; Instabox keeps a machine's files and can run with idle pause turned off, Cloudflare wipes the disk on sleep, and boat keeps the disk across stops. | 207th of 366, with limits $2,188 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 short code-interpreter calls Cloudflare fits well, since CPU is billed only while busy and a container wakes on the next request; Instabox's API exec calls run at most 10 minutes, 4 at once. | 13th cheapest of 345 $144 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 Cloudflare can run up to 1,500 vCPU at once for your users, while Instabox allows 5 machines per account, paused and stopped ones included, so it cannot yet give a sandbox to each of many users. | 9th cheapest of 361 $731 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 | 144th of 360, with limits $9,428 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 Cloudflare's account limits leave room for many evals in parallel; Instabox's 5-machine cap keeps it to a handful at a time. | 45th cheapest of 364 $818 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 or Android apps need disk and /dev/kvm; Cloudflare caps disk at 20 GB by default and turns off iptables for Docker, Instabox has 20 GB of storage and does not document /dev/kvm, and boat has both. | 301st of 377, with limits $704 a month | No published price | 4th cheapest of 377 $86 a month |
| 24/7 dev boxes 1 machine 24/7 · 4 vCPU / 8 GB Instabox makes a pleasant cloud dev box with SSH, mosh and a pause that keeps memory; Cloudflare starts from a fresh disk after sleep, and boat stops at no cost and resumes with its disk. | 70th cheapest of 368 $93 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 template with screenshot and click control, Cloudflare removed its built-in desktop so you would build your own, and boat streams a desktop at 60fps with a computer-use agent. | 166th of 369, with limits $460 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 | 210th of 367, with limits $233 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 | 250th of 346, with limits $286 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 | 169th of 338, with limits $5,741 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 | 239th of 360, with limits $325 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 | Cloudflare Sandbox | Instabox | boat |
|---|---|---|---|
| Isolation | Firecracker microVM per container, own kernel and network | Firecracker microVM per machine, own kernel and root | Full VM with its own kernel on dedicated AMD Ryzen 9 9950X hosts |
| Machine sizes | Up to 4 vCPU / 12 GiB / 20 GB disk by default (can be raised); 4 vCPU always comes with 12 GiB | 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 |
| How many at once | Account limit of 1,500 vCPU, 6 TiB memory and 30 TB disk running at once (can be raised) | 5 machines per account, paused and stopped ones included | No session cap on paid plans; starts per hour and per day are limited by plan |
| Files between sessions | Disk is fresh after sleep; snapshots (public beta, 30 days) or R2 backups when your code saves them | A machine keeps its files while paused or stopped; snapshots saved by hand, up to 10 | Disk saved every minute and on stop; a stopped sandbox costs nothing |
| Idle and pause | Stops after inactivity and wakes on the next request; memory and processes are lost | Pauses after 30 idle minutes by default, keeping memory and running programs; resume usually takes about a second | TTL based stop (1 h default, changeable); disk kept, the machine boots again on start |
| Fork | No fork; restore a saved snapshot or backup into a new sandbox | Fork copies a stopped machine only | Fork a running sandbox with its disk, without stopping it |
| Docker inside | docker:dind with iptables and IP forwarding turned off | Docker and Docker Compose run inside | Full Docker and Compose, with root and systemd |
| Nested virtualization | Not documented | Not documented | Yes, /dev/kvm for Android emulators and VMs |
| Desktop and computer use | Built-in desktop removed in SDK 0.10.2; bring your own | 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, a computer-use agent and an embeddable stream |
| Inbound traffic | HTTP and WebSocket previews routed through your Worker; no raw TCP or public IP | HTTPS on up to 16 ports, open to anyone with the URL; offline while the machine is paused | HTTPS URLs for up to 50 ports, token-protected by default; raw TCP too |
| Egress control | allowedHosts deny-by-default list plus outbound handlers you write in Worker code | Not documented | No provider-side allowlist |
| Keeping API keys out of the sandbox | Your outbound handler adds the token for any HTTP or HTTPS host; you write the code | Vault writes your secrets into each machine as environment variables or files | Managed proxy for model providers and any HTTPS API you register; real keys never enter the sandbox |
| Coding agents | Run Claude Code, Codex, OpenCode or Pi in your image; OpenCode has an SDK helper | Templates and saved agent sign-ins in snapshots; you run the agent yourself | Seven agents preinstalled, with a prompt, steer and events API |
| Regions | Several regions across Cloudflare's network, nearest free one picked | Not published | EU only: Germany, Finland, France |
Every feature Battleships tracks (43)
| Feature | Cloudflare Sandbox | 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 | Not published | Not published | Yes |
| Desktop GUI | No | Yes | Yes |
| Browser | No | Yes | Yes |
| Computer-use API | No | Yes | Yes |
| SSH | Yes | Yes | Yes |
| Persistent disk | No | Yes | Yes |
| Pause/resume | No | Yes | Yes |
| Automatic snapshots | No | No | Yes |
| Fork/clone | No | Yes | Yes |
| Live fork (no pause) | No | 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 | No | Not published | Yes |
| Public IPv4 | No | No | No |
| Egress allowlist | Yes | Not published | No |
| Secret proxy | Yes | No | Yes |
| Secret proxy for any API | Yes | No | Yes |
| Preinstalled agents | Yes | Not published | Yes |
| Agent harness API | Yes | Not published | Yes |
| MCP server | No | 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) | 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
Neither Cloudflare Sandbox nor Instabox has a result on the hpc-sandbox-benchmarks Node.js build-and-test loop, so this page makes no speed claim between them. boat did 26.69 runs per second on that loop at 4 vCPU / 8 GB. Instabox says a new machine's shell is ready in under a second; that has not been measured here.
Node.js build-and-test loop at 4 vCPU / 8 GB, higher is better. Measured with the open hpc-sandbox-benchmarks suite. Cloudflare Sandbox 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 | Cloudflare Sandbox, 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 | $39 · Workers Paid · 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 | $148 · Workers Paid · 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 | $1,660 · Workers Paid · 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 | $476 · Workers Paid | 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 | $1,889 · Workers Paid · with limits | No published price | $2,000 · $2000/mo · with limits |
Cloudflare Sandbox: You need Workers Paid ($5 a month minimum). CPU is billed only while in use; memory and disk are billed on the instance size you picked, in 10 ms steps, until the container sleeps, and 4 vCPU always comes with 12 GiB.
Instabox: Instabox is free during the beta ("Free until we figure it out"), with 5 machines per user. It publishes no price or rate, so no bill can be compared with Cloudflare or boat yet.
Instabox: Plans start at $20 a month, and the whole fee is usage credit, billed per second while a sandbox runs. A stopped sandbox costs nothing and keeps its disk.
Limits in those scenarios
Cloudflare's disk resets after sleep and tops out at 20 GB by default, so the scenarios that keep 50 GB of files between days do not fit without your own snapshot or backup code, and its 1,500 vCPU account limit is short of the 2,000 vCPU the 1,000-job burst needs unless raised. Instabox allows 5 machines per account, paused and stopped ones included, with 20 GB of storage each, so the 50-agent and user-sandbox scenarios do not fit it today, and it has no published rate to price any scenario. boat fits every scenario but the burst, where its start limits per hour and per day are lower than 1,000 short jobs need.
| Scenario | Cloudflare Sandbox | 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 Cloudflare Sandbox when
your app already runs on Workers and you want many short sandboxes that sleep when idle, wake on request and follow egress rules you write.
- Egress rules you can program. For teams that must limit where code connects: block every host except the ones you list, and run your own code on each outbound request.
- Sleeps when idle, wakes on request. For many short, spiky sessions: a sandbox sleeps when idle, wakes on the next request, and bills CPU only while busy.
- Room to scale inside Workers. For apps already on Workers: up to 1,500 vCPU at once by default, in several regions, next to Durable Objects and R2.
Use Instabox when
you want to try a few free 4 vCPU / 8 GiB agent machines during its invite-only beta, with a pause that keeps memory and mosh over SSH.
- Pause with memory. A paused machine keeps its memory and running programs, and its docs say it usually resumes in about a second.
- SSH gateway with mosh. For people who live in a terminal: SSH with short-lived certificates, paste-anywhere SSH tokens, and mosh that survives sleep and network changes.
- Free during the beta. For trying things out: during the invite-only beta each user gets 5 machines of 4 vCPU / 8 GiB at no charge.
Where boat fits
Look at boat when your agents work for hours on one machine and need it to keep its files, run full Docker or emulators, and branch without stopping. Cloudflare Sandbox is built for short sessions that sleep and wipe, and Instabox is a one-size beta capped at 5 machines; boat gives you several sizes, published terms and a whole VM.
Work that is kept and can branch
On Cloudflare a sleeping sandbox comes back with an empty disk unless your code saves a snapshot. On Instabox a fork or snapshot stops the machine first. boat saves the disk every minute and forks a running sandbox.
A machine big enough for real builds
Cloudflare tops out at 20 GB of disk by default and runs Docker with iptables off; Instabox has one 4 vCPU / 8 GiB size with 20 GB. Neither documents /dev/kvm. boat goes up to 16 vCPU / 32 GB with full Docker and /dev/kvm.
Agents, keys and URLs handled for you
On Cloudflare you bake agents into your image and write the code that adds every token. Instabox writes secrets into the machine and its port URLs are open to anyone. boat drives agents inside from outside, keeps keys out and token-protects URLs.
Use boat when your agents do real work for hours: full Docker, emulators and a desktop, on a machine that keeps its files, forks while running and comes in several sizes. Compare it one to one: boat vs Cloudflare Sandbox and boat vs Instabox.
Questions people ask
Is Cloudflare Sandbox cheaper than Instabox?
It can't be compared yet. Instabox is free during its beta and publishes no price, so there is no bill to set against Cloudflare's. Cloudflare needs Workers Paid and bills CPU while busy plus memory and disk until the container sleeps.
Which is faster, Cloudflare Sandbox or Instabox?
Neither has been measured on the same CPU benchmark, so there is no fair answer yet. boat did 26.69 runs per second on the hpc-sandbox-benchmarks Node.js loop at 4 vCPU / 8 GB.
Can Cloudflare Sandbox and Instabox run Docker?
Yes, both. Cloudflare supports docker:dind with iptables and IP forwarding turned off, and Instabox runs Docker and Docker Compose inside. boat runs full Docker with root and systemd.
Do they keep my files between sessions?
Instabox keeps a machine's files while it is paused or stopped. Cloudflare starts from a fresh disk after sleep unless your code saved a snapshot (public beta, kept 30 days) or a backup to R2. boat saves the disk every minute and on stop.
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.
Can I fork a running sandbox?
Not on either. Cloudflare has no fork, only restoring a saved snapshot or backup, and Instabox's fork copies a stopped machine. boat forks a running sandbox and keeps the original working.
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