CodeSandbox SDK vs Azure Container Apps Sandboxes
Both give each sandbox its own microVM that can sleep with its memory and wake on traffic. CodeSandbox SDK is a standalone service that Together now calls its legacy SDK, while Azure Container Apps Sandboxes lives inside your Azure account, with egress rules, VNets and 40 regions.
The companies and products
CodeSandbox SDK
CodeSandbox SDK is an API from CodeSandbox, now a Together AI company, that starts sandboxed development VMs on the same infrastructure as the CodeSandbox editor.
Each sandbox is a Firecracker microVM built from a template or any Dockerfile. When it goes idle it hibernates with a memory snapshot, and it resumes or forks from that snapshot in seconds. You drive it from a TypeScript SDK through terminals, commands, files and HTTPS hosts. Together's docs now call it the legacy offering and point new users to its successor, the together-sandbox SDK.
Azure Container Apps Sandboxes
Azure Container Apps Sandboxes is a service inside Microsoft Azure that gives each agent or user an isolated microVM you create, suspend and resume through an SDK.
It is part of Azure Container Apps, the hyperscaler's serverless container platform, and lives in your Azure subscription as a sandbox group resource. Each sandbox boots from an OCI image or a snapshot, has its own kernel, and can be suspended with its memory and resumed in under a second. It is built for teams already on Azure that want stateful code execution with Azure networking, identity and billing.
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. “46th cheapest of 345” means 45 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 | CodeSandbox SDK: price rank | Azure Container Apps Sandboxes: price rank | boat: price rank |
|---|---|---|---|
| Software factory 100 at once · 4 vCPU / 8 GB · 2,200 sessions of 8 h a month Neither offers SSH or documented nested virtualization, so long agent builds with emulators fit boat, which has both plus a desktop. | 178th of 367, with limits $1,939 a month | 288th of 367, with limits $5,276 a month | 3rd cheapest of 367 $634 a month |
| Always-on AI employees 50 machines 24/7 · 2 vCPU / 4 GB | 215th of 366, with limits $2,478 a month | 302nd of 366, with limits $6,544 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 Both fit short code runs well, since each sleeps with its memory and wakes on the next request; Azure bills per second instead of per started minute. | 46th cheapest of 345 $642 a month | 34th cheapest of 345 $354 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 Azure fits this one fully and CodeSandbox SDK only as a compromise, because the Scale plan stops at 250 VMs at once; boat fits it too. | 140th of 361, with limits $1,707 a month | 22nd cheapest of 361 $2,260 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 Both can seed many rollouts from one memory snapshot; CodeSandbox SDK can also fork a running sandbox while it shares memory with its parent. | 348th of 360, with limits $3,861 a month | 153rd of 360, with limits $10,740 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 | 64th cheapest of 364 $1,335 a month | 75th cheapest of 364 $1,728 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 Both run Docker builds, but jobs that need /dev/kvm for Android emulators or VM images only run on boat. | 92nd cheapest of 377 $860 a month | 103rd cheapest of 377 $1,046 a month | 4th cheapest of 377 $86 a month |
| 24/7 dev boxes 1 machine 24/7 · 4 vCPU / 8 GB Neither gives SSH, so editors that connect over SSH need a workaround on both; every boat sandbox has SSH and costs nothing while stopped. | 310th of 368, with limits $240 a month | 322nd of 368, with limits $262 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 Both are headless, so a computer-use agent needs a desktop you build yourself; boat streams one at 60fps in every sandbox. | 206th of 369, with limits $691 a month | 279th of 369, with limits $1,573 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 CodeSandbox SDK has a headless Chromium template and Azure ships no browser image; boat has Chromium on a desktop ready to go. | 251st of 367, with limits $443 a month | 288th of 367, with limits $795 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 | 281st of 346, with limits $508 a month | 284th of 346, with limits $561 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 | 193rd of 338, with limits $7,390 a month | 239th of 338, with limits $10,956 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 | 240th of 360, with limits $326 a month | 278th of 360, with limits $517 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 | CodeSandbox SDK | Azure Container Apps Sandboxes | boat |
|---|---|---|---|
| Isolation | Firecracker microVM with its own kernel | MicroVM per sandbox with its own kernel | Full VM with its own kernel on dedicated AMD Ryzen 9 9950X hosts |
| Biggest machine | Up to 16 cores / 32 GB on Scale, 64 cores / 128 GB on Enterprise | Tiers up to 4 cores / 8 GB; up to 16 vCPU / 32 GB by API | Up to 16 vCPU / 32 GB on the $100 plan and above |
| Sleep and wake | Hibernates with a memory snapshot; an HTTP request to a host wakes it with processes running | Suspends with memory and disk; resumes in under a second on traffic or a start command | Disk is saved every minute and on stop; a stopped sandbox is started by API and boots again |
| Fork | Fork a hibernated sandbox from its snapshot, or a running one sharing its memory | Snapshot a running sandbox with its memory and create new sandboxes from it | Fork a running sandbox with its disk |
| Nested virtualization | Not documented | Not documented | Yes, /dev/kvm for Android emulators and VMs |
| Docker and root | Docker and root; built from any Dockerfile | Depends on the image: azure-dev ships Docker on systemd; the default ubuntu image has only Buildah | Docker, systemd and root on every sandbox |
| Getting a shell | Terminals, commands and files through the SDK; no SSH | Interactive shell through the aca CLI, SDK or portal; no SSH | SSH, plus exec and files over the API |
| Inbound access | HTTPS host per port, public by default, signed tokens for private hosts; no raw TCP or public IP | Public HTTPS routes per published port; private endpoint from your VNet at extra cost; no public IP | HTTPS URLs for up to 50 ports, token-protected by default; raw TCP; a dedicated IPv6 or IPv4 |
| Desktop and browser | No desktop; a headless Chromium template | Headless; no desktop or managed browser | Linux desktop streamed at 60fps, Chromium and computer-use tools |
| Coding agents | Run your own agent through the command API | Copilot CLI and Claude Code images, run through the exec API | Seven agents preinstalled, with a prompt, steer and events API |
| Keeping API keys out of the sandbox | Secrets passed in as environment variables | Group secrets usable in egress header rules; Copilot and Anthropic tokens are injected into the sandbox at startup | Credentials proxy for model providers and any HTTPS API; switch a credential to another account when credits run out |
| Outbound rules | No egress allowlist | Egress policy with allow, deny, rewrite and header rules by host, path and method; VNet integration | Open internet, no provider-side allowlist |
| Sandboxes at once | 250 VMs on Scale; more through Enterprise sales | 500 concurrent active cores by default; more by Azure support request | Concurrency set by plan, up to 2,000 sandboxes, self-serve |
| Regions | No region choice; a country hint steers scheduling, for example to Europe, without a guarantee | 40 Azure regions, 9 of them in the EU | EU only (Germany, Finland, France) |
Every feature Battleships tracks (43)
| Feature | CodeSandbox SDK | Azure Container Apps Sandboxes | boat |
|---|---|---|---|
| Full VM (own kernel) | Yes | Yes | Yes |
| Docker inside | Yes | Yes | Yes |
| Nested virtualization | No | No | Yes |
| Root | Yes | Yes | Yes |
| Systemd | Not published | Yes | Yes |
| Desktop GUI | No | No | Yes |
| Browser | No | No | Yes |
| Computer-use API | No | No | Yes |
| SSH | No | 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 | Yes | Yes |
| Memory fork | Yes | 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 | No | No | Yes |
| Public IPv4 | No | No | No |
| Egress allowlist | No | 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 | No | No | No |
| GPU | No | No | No |
| Windows | No | No | No |
| Arm64 | No | No | No |
| Self-hosting | No | No | No |
| BYOC | No | No | No |
| Open source | No | No | No |
| Scoped API keys | Not published | Not published | Yes |
| Spend limits | Not published | Yes | Yes |
| Usage per sandbox (API) | No | Yes | Yes |
| Audit logs | Not published | Yes | No |
| SSO | Yes | Yes | No |
| SOC 2 | Yes | Yes | No |
| HIPAA | No | Yes | No |
| EU data residency | No | Yes | Yes |
| Zero data retention | Not published | Not published | Yes |
Performance
Neither CodeSandbox SDK nor Azure Container Apps Sandboxes has a comparable CPU measurement yet, so this page makes no speed claim between them. boat did 26.69 runs per second on the StarSling hpc-sandbox-benchmarks Node.js loop at 4 vCPU / 8 GB, on dedicated AMD Ryzen 9 9950X hosts.
Node.js build-and-test loop at 4 vCPU / 8 GB, higher is better. Measured with the open hpc-sandbox-benchmarks suite. CodeSandbox SDK and Azure Container Apps Sandboxes 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 | CodeSandbox SDK, a month | Azure Container Apps Sandboxes, 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 | $193 · Scale | $68 · Pay-as-you-go | $20 · $20/mo |
| One agent that never stops 4 vCPU / 8 GB, 50 GB disk, running 24/7 all month | $341 · Scale | $262 · Pay-as-you-go · with limits | $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 | $2,500 · Scale | $3,421 · Pay-as-you-go | $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 | $815 · Scale · with limits | $989 · Pay-as-you-go | $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 | $1,632 · Scale · with limits | $2,148 · Pay-as-you-go | $2,000 · $2000/mo · with limits |
CodeSandbox SDK: You buy VM credits and each size burns a fixed number per hour, billed per started minute while the VM runs, idle time before hibernation included. Scale adds a $170 monthly platform fee that is not usage credit.
Azure Container Apps Sandboxes: Azure bills per second on the Container Apps Consumption meters for the vCPU and memory of the sandbox's tier while it runs, idle time before auto-suspend included. There is no plan fee, and some regions charge more per second.
Azure Container Apps Sandboxes: Plans start at $20 a month, and the whole fee is usage credit. You pay per second while a sandbox runs, and a stopped sandbox costs nothing and keeps its disk.
Limits in those scenarios
CodeSandbox SDK's Scale plan allows 250 VMs at once, so the user-sandboxes and 1,000-job scenarios do not fit it, and the price for disk beyond 20 GB and for egress is not published. Azure has no plan cap, but a sandbox that runs all month only gets near $262 a month with a 3-year commitment, and its default quota of 500 active cores needs a support request to grow. boat fits every scenario but the 1,000-job burst, where even the $2,000 plan queues starts.
| Scenario | CodeSandbox SDK | Azure Container Apps Sandboxes | boat |
|---|---|---|---|
| One coding agent, workdays |
| None that bite | None that bite |
| One agent that never stops |
|
| 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 |
| None that bite |
|
Which one should you use?
Use CodeSandbox SDK when
you want standalone sandboxes outside any cloud account, need very large machines or forks of running memory, and are fine building on what Together now calls its legacy SDK.
- Very large machines. Teams that need one big machine can get up to 64 cores and 128 GB on Enterprise, past Azure's 16 vCPU.
- Forks that share live memory. You can fork a running sandbox while it shares memory with its parent, handy for branching many runs from one warm state.
- No cloud account needed. Sign up through CodeSandbox and build sandboxes from any Dockerfile, with no Azure subscription or Entra ID roles to set up.
Use Azure Container Apps Sandboxes when
your team already runs on Azure and wants short stateful sandboxes behind strict egress rules, in regions outside the EU, or in bursts of thousands.
- Fine-grained outbound rules. Its egress policy can allow, deny or rewrite each outbound request by host, path and method, and join your VNets.
- Inside Azure, in 40 regions. Teams already on Azure get Entra ID, Azure billing and their own networks, in 40 regions on six continents.
- Room for big bursts. With no 250-VM plan cap and per-second billing, it fits the user-sandbox and 1,000-job scenarios that CodeSandbox SDK's Scale plan does not.
Where boat fits
Both of these are built for short, stateful code runs that sleep between requests. If your agents instead work for hours on installs, builds, emulators, a browser and servers other people reach, boat gives each one a whole machine with the agent and its keys already set up.
A whole machine with SSH and KVM
Neither CodeSandbox SDK nor Azure offers SSH or documents nested virtualization, so Android emulators and VM tests cannot start, and every tool goes through an SDK or exec call. boat has SSH, systemd and /dev/kvm.
A screen and a browser
Both are headless, so a computer-use agent needs you to build a browser, a virtual display and a streaming stack into your image. Every boat sandbox streams a Linux desktop at 60fps with Chromium.
Agents and keys built in
On CodeSandbox SDK keys go in as environment variables, and Azure injects agent tokens into the sandbox, where a prompt-injected agent can read them. boat keeps keys in a proxy outside and ships agents you drive from outside.
Use boat when your agents do real work for hours: SSH, Docker, emulators, a desktop and a browser, with coding agents and a credentials proxy built in. Compare it one to one: boat vs CodeSandbox SDK and boat vs Azure Container Apps Sandboxes.
Questions people ask
Is CodeSandbox SDK cheaper than Azure Container Apps Sandboxes?
It depends on the job. For one coding agent on workdays Azure comes to $68 a month against $193 on CodeSandbox SDK, while 50 agents in parallel come to $2,500 a month on CodeSandbox SDK against $3,421 on Azure. boat costs less than both in every scenario it fits.
Which is faster, CodeSandbox SDK or Azure Container Apps Sandboxes?
Neither has a comparable CPU measurement yet, so there is no fair speed answer. Both resume from memory: Azure says in under a second, and CodeSandbox SDK resumes from its snapshot in seconds.
Can I run Docker in each?
CodeSandbox SDK runs Docker with root and builds sandboxes from any Dockerfile. On Azure it depends on the image: azure-dev ships Docker on systemd, while the default ubuntu image has only Buildah. boat runs Docker and systemd on every sandbox, with /dev/kvm too.
Can I SSH into a CodeSandbox SDK or Azure sandbox?
No. CodeSandbox SDK connects through its SDK terminals, commands and files, and Azure gives a shell through the aca CLI, SDK or portal. Every boat sandbox has SSH as well as an exec and files API.
Is CodeSandbox SDK still maintained?
CodeSandbox is now part of Together AI. Together's docs call the CodeSandbox-based SDK deprecated and name together-sandbox as its successor, while self-serve sign-up still runs through CodeSandbox.
Do I need an Azure account for Azure Container Apps Sandboxes?
Yes. It needs an Azure subscription, a Microsoft Entra ID account and the Container Apps SandboxGroup Data Owner role. CodeSandbox SDK and boat each have their own sign-up.
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