Northflank vs Agent 37
Northflank runs sandboxes as one part of a big cloud platform, with microVMs, GPUs, many regions and your own cloud. Agent 37 hosts one always-on agent per user in the US, on light gVisor sandboxes that sleep when idle and keep their memory.
The companies and products
Northflank
Northflank is a London developer platform for running services, jobs and databases on Kubernetes, and Sandboxes is its product for running untrusted code.
A Northflank sandbox is a container image deployed as a service: CPU sandboxes run in Kata microVMs with their own kernel, and GPU sandboxes run under gVisor. You create and drive them from the JavaScript or Python SDK, the CLI or the dashboard, on Northflank's cloud or inside your own. It suits teams that already want one platform for apps, databases, GPUs and sandboxes.
Agent 37
Agent 37 hosts AI agents, one isolated, always-on sandbox per user, behind one API.
You create an instance from a template (Hermes, OpenClaw, Claude Code, Codex, OpenCode, Pi, Grok or your own Docker image) and talk to it through a chat API, files, exec, SSH and HTTPS URLs. The default instance is a container enforced by gVisor; a VM type gives a full Linux machine with its own kernel for Docker, Kubernetes and Android emulators. It is built for companies that give each of their customers an agent.
- Where it runs
- Dedicated servers in the United States
- Instance types
- Default (shared), Performance (dedicated cores), VM
- Compliance
- SOC 2 Type I, Type II in progress
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. “38th cheapest of 377” means 37 of the other 376 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 | Northflank: price rank | Agent 37: price rank | boat: price rank |
|---|---|---|---|
| Software factory 100 at once · 4 vCPU / 8 GB · 2,200 sessions of 8 h a month A coding agent installs packages all over the machine; Northflank keeps only attached volumes across a pause, Agent 37 keeps the disk, and boat keeps the whole disk with Docker and systemd. | 159th of 367, with limits $1,477 a month | 2nd cheapest of 367 $551 a month | 3rd cheapest of 367 $634 a month |
| Always-on AI employees 50 machines 24/7 · 2 vCPU / 4 GB This is what Agent 37 is built for: one assistant per user that sleeps when idle and wakes on the next message, ranked 1st here against 173rd for Northflank. | 173rd of 366, with limits $1,365 a month | Cheapest of 366 $279 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 Short code runs on small machines suit both: Northflank has per-second plans from a tenth of a vCPU, and Agent 37's small default sandboxes cost even less. | 84th of 345, with limits $115 a month | Cheapest of 345 $22 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 Agent 37 stops at 200 instances on its top self-serve tier, counting sleeping ones, and Northflank does not publish its limit; boat plans go up to 2,000 at once. | 89th of 361, with limits $815 a month | 30th of 361, with limits $79 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 | 342nd of 360, with limits $1,762 a month | 6th of 360, with limits $363 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 | 134th of 364, with limits $689 a month | 90th of 364, with limits $58 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 All three fit; Agent 37 is the cheapest here, and boat adds /dev/kvm for Android emulators and VM builds. | 38th cheapest of 377 $352 a month | 2nd cheapest of 377 $84 a month | 4th cheapest of 377 $86 a month |
| 24/7 dev boxes 1 machine 24/7 · 4 vCPU / 8 GB | 151st of 368, with limits $59 a month | 3rd cheapest of 368 $12 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 Agent 37 adds a noVNC desktop through a template, Northflank sandboxes are headless, and boat streams a 60fps desktop with Chromium out of the box. | 151st of 369, with limits $371 a month | Cheapest of 369 $53 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 | 200th of 367, with limits $194 a month | 48th of 367, with limits $29 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 | 196th of 346, with limits $117 a month | Cheapest of 346 $32 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 | 83rd of 338, with limits $2,049 a month | 36th of 338, with limits $648 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 Agent 37 is cheapest for many small parallel tries, but has no fork; boat can fork a running machine to try many paths from the same point. | 141st of 360, with limits $99 a month | Cheapest of 360 $43 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 Only Northflank has GPU sandboxes, from L4 to H100 and up; Agent 37 and boat are CPU only. | 4th cheapest of 98 $693 a month | 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 | Northflank | Agent 37 | boat |
|---|---|---|---|
| Isolation | Kata microVM with its own kernel for CPU; gVisor for GPU | gVisor by default; full VM as an opt-in instance type | Every sandbox is a full VM with its own kernel on dedicated AMD Ryzen 9 9950X hosts |
| Docker inside | Yes, each sandbox has its own kernel | Only on the VM type, at 2.5x the default compute rate | Yes, in every sandbox |
| Nested virtualization | Not documented inside a sandbox | /dev/kvm on the VM type, with an Android template | /dev/kvm in every sandbox, Android emulators work |
| What survives a stop | Only attached volumes, billed while paused; the rest of the disk and all processes reset | The disk, billed while stopped; memory is checkpointed on auto-sleep | The whole disk, saved every minute and on stop; a stopped sandbox costs nothing, and it reboots on resume |
| Sleep when idle | No idle auto-pause; bills until you pause it | Opt-in auto-sleep after a quiet period, wakes on the next request | No idle timer; a time limit you set, or no limit |
| Snapshots and fork | Filesystem snapshots, opt-in; restore into a new sandbox | No fork; daily backups plus one on-demand backup, restored in place only | Fork a running sandbox; snapshots every minute; named snapshots as templates |
| Desktop and browser | Headless; access by SDK, browser terminal or SSH | noVNC desktop through a template build or the Ubuntu VM template | 60fps Linux desktop, Chromium and computer use in every sandbox |
| Coding agents | Harnesses with Claude Code, Codex, Cursor, OpenCode or Pi, reached by terminal or SSH | Hermes, OpenClaw, Claude Code, Codex, Grok, OpenCode, Pi, with a chat API per instance | Seven agents preinstalled, with a prompt, steer and events API |
| Keeping API keys out | Header injection for listed hosts in the network policy API; otherwise env vars or files | Managed models, search and Composio through a per-instance token; your own keys go in as env vars | Credentials proxy for model providers and any HTTPS API; switch to another account when credits run out |
| Inbound access | HTTPS ports on a code.run domain; TCP and UDP need a separate load balancer | HTTPS URL per port, custom domains; no public IP, SSH through a WebSocket tunnel | HTTPS URLs for up to 50 ports, raw TCP, dedicated IPv4 or IPv6 |
| Outbound rules | Network policies with allow lists by IP, CIDR or domain | Open internet, no allowlist | Open internet, no provider-side allowlist |
| GPUs | L4, A100, H100, RTX PRO 6000 and more | No | No |
| Regions | US, Europe, Asia, Australia, South America and Africa | United States | EU only (Germany, Finland, France), EU data residency |
Every feature Battleships tracks (43)
| Feature | Northflank | Agent 37 | boat |
|---|---|---|---|
| Full VM (own kernel) | Yes | No | Yes |
| Docker inside | Yes | No | Yes |
| Nested virtualization | No | No | Yes |
| Root | Not published | 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 | 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 | No | No | No |
| Custom image (Docker or snapshot) | Yes | Yes | Yes |
| ≥24 h sessions | Yes | Yes | Yes |
| Idle auto-stop | No | Yes | No |
| Wake on request | No | Yes | No |
| HTTPS preview URLs | Yes | Yes | Yes |
| Raw TCP inbound | Yes | Not published | Yes |
| Public IPv4 | No | No | No |
| Egress allowlist | Yes | No | No |
| Secret proxy | Yes | Yes | Yes |
| Secret proxy for any API | Yes | No | Yes |
| Preinstalled agents | Yes | Yes | Yes |
| Agent harness API | No | Yes | Yes |
| MCP server | No | No | No |
| GPU | Yes | No | No |
| Windows | No | No | No |
| Arm64 | Yes | No | No |
| Self-hosting | Yes | No | No |
| BYOC | Yes | 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) | Yes | Yes | Yes |
| Audit logs | Yes | Not published | No |
| SSO | Yes | No | No |
| SOC 2 | Yes | Yes | No |
| HIPAA | Yes | No | No |
| EU data residency | Yes | No | Yes |
| Zero data retention | Not published | Not published | Yes |
Performance
Neither Northflank Sandboxes nor Agent 37 has a result on the hpc-sandbox-benchmarks test, so there is no comparable CPU measurement for either. boat did 26.69 runs per second on that Node.js build-and-test loop at 4 vCPU / 8 GB. Agent 37 says its default instances share host resources, and sells a Performance type on dedicated cores.
Node.js build-and-test loop at 4 vCPU / 8 GB, higher is better. Measured with the open hpc-sandbox-benchmarks suite. Northflank and Agent 37 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 | Northflank, a month | Agent 37, 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 | $32 · Developer Sandbox (free tier) · with limits | $6 · Wallet (any top-up) | $20 · $20/mo |
| One agent that never stops 4 vCPU / 8 GB, 50 GB disk, running 24/7 all month | $108 · Developer Sandbox (free tier) · with limits | $12 · Wallet (any top-up) | $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 | $1,322 · Developer Sandbox (free tier) · with limits | $329 · Wallet ($100 lifetime top-ups) | $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 | $361 · Developer Sandbox (free tier) · with limits | $33 · Wallet ($250 lifetime top-ups) · with limits | $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 | $688 · Developer Sandbox (free tier) · with limits | $73 · Wallet ($250 lifetime top-ups) · with limits | $2,000 · $2000/mo · with limits |
Northflank: Northflank bills per second for the plan size you pick, with no monthly fee, until you pause the sandbox; there is no idle auto-pause. Volumes cost $0.15 per GB a month even while paused, and outbound traffic costs $0.06 per GB.
Agent 37: Agent 37 uses a prepaid wallet metered per minute: $0.80 per vCPU and $0.70 per GB of RAM a month while running, and $0.09 per GB of disk even while asleep. Performance compute costs 4x and VM compute 2.5x the default rate.
Limits in those scenarios
On Northflank the limit that bites is what survives a stop: only attached volumes keep their files, and it does not publish how many sandboxes can run at once, so 300 or 1,000 at a time is not confirmed. Agent 37 caps instances at 200 on its top self-serve tier, counting sleeping and stopped ones, so the 300 user sandboxes and the 1,000-job burst do not fit. Its 50-agent scenario needs Docker, so it is priced on the VM type at 2.5x compute. boat's limit is the burst: even the $2,000 plan queues starts above 90 a minute.
| Scenario | Northflank | Agent 37 | 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 |
| 1,000 short jobs at once |
|
|
|
Which one should you use?
Use Northflank when
you need GPUs next to the agent, regions outside the US and Europe, or sandboxes inside your own cloud next to your other apps.
- GPU sandboxes. For agents that train or run models: Northflank has GPU sandboxes from L4 to H100 and up.
- Regions around the world. For users spread across the globe: Northflank runs in the US, Europe, Asia, Australia, South America and Africa.
- Your own cloud, and one platform. For teams that must run in their own AWS, GCP or Azure account, next to their services and databases.
Use Agent 37 when
you host one mostly idle assistant per customer in the US that should sleep with its memory kept and wake on the next message.
- Sleeps when idle and keeps its memory. For assistants idle most of the day: an instance sleeps, keeps its memory and wakes on the next message.
- The lowest bill here. For many small, mostly idle agents: Agent 37 costs less than Northflank in every scenario below.
- Your Dockerfile, or dedicated cores. Agent 37 builds templates from your own Docker image, and sells a Performance type on dedicated cores.
Where boat fits
If your agents do real work for hours, like installs, builds, Docker and emulators, look at boat. Every boat sandbox is a full VM that keeps its whole disk, can be forked while it runs, and has the agent, a desktop and a browser inside.
A full VM is the default
On Agent 37 Docker needs the VM type at 2.5x the compute rate, with no init system. Northflank does not document /dev/kvm, so Android emulators are out. boat has Docker, systemd and /dev/kvm everywhere.
The whole machine comes back, or forks
A Northflank pause wipes everything outside attached volumes, which bill $0.15 per GB a month while paused. Agent 37 has no fork, and backups restore only in place. boat saves the whole disk and forks running sandboxes.
Agents and keys run from outside
Northflank harnesses are reached through a terminal or SSH, and Agent 37 puts your own API keys inside the machine as env vars. boat gives a prompt, steer and events API, and a credentials proxy for any HTTPS API.
Use boat when your agents work on one machine for hours and should find it as they left it, with Docker, emulators, a desktop and a browser, forks of running machines and the agent driven from your code. Compare it one to one: boat vs Northflank and boat vs Agent 37.
Questions people ask
Is Northflank cheaper than Agent 37?
No. Agent 37 costs less in all five scenarios on this page: one agent that never stops is $12 a month on Agent 37 against $108 on Northflank. Agent 37's self-serve tiers stop at 200 instances, though, so the 300 and 1,000 at once scenarios do not fit.
Which is faster, Northflank or Agent 37?
There is no comparable CPU measurement for either on the hpc-sandbox-benchmarks test. boat did 26.69 runs per second on it at 4 vCPU / 8 GB. Agent 37 sells a Performance type on dedicated cores for steady speed.
Can I run Docker on Northflank and Agent 37?
On Northflank each CPU sandbox is a Kata microVM with its own kernel, so Docker can run inside. On Agent 37 Docker works only on the VM type, which bills compute at 2.5x; the default gVisor type cannot run a Docker daemon. boat runs Docker in every sandbox.
Does a sandbox keep its files when it stops?
On Northflank only files on attached volumes survive a pause. Agent 37 keeps the disk, and on auto-sleep it also checkpoints memory. boat keeps the whole disk on every stop, and a stopped sandbox costs nothing.
Do Northflank or Agent 37 have GPUs?
Northflank has GPU sandboxes under gVisor with cards from L4 to H100 and more. Agent 37 has no GPUs, and boat runs on CPUs only.
Where do Northflank and Agent 37 run?
Northflank runs in many regions across the US, Europe, Asia, Australia, South America and Africa, or in your own cloud. Agent 37 runs on dedicated servers in the United States. boat runs only in the EU, with EU data residency.
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