Sandboxer vs Agent37

Agent37 is a managed service for hosting agent harnesses in persistent sandboxes, with standard sandboxes under gVisor and full VMs with their own kernel. It differs from Sandboxer in its low metered pricing and bundled model access, while Sandboxer focuses on full VMs with nested KVM and memory-preserving stop. Pick Agent37 for cheap always-on agent hosting; pick Sandboxer for heavier VM workloads.

Checked against Agent37's public docs on October 24, 2026. Sources are linked in the table and listed below.

At a glance

Sandboxer and Agent37 compared
Capability	Sandboxer	Agent37
Isolation	microVM Cloud Hypervisor, its own kernel	gVisor (standard); full VM with own kernel (VM type) Standard shape shares host resources; VM type costs 2.5x the compute rate.
Full Linux with root	Ubuntu 24.04, sudo, systemd
Docker inside	Preinstalled	partial Bring your own Docker image; the agent37-ubuntu VM template (Ubuntu 26.04) has Docker, Compose and buildx installed and starts dockerd on boot.
Nested virtualization (/dev/kvm)		partial VM instances (2.5x compute) have /dev/kvm inside, e.g. for hardware-accelerated Android emulators; standard gVisor sandboxes do not state it.
Pause and resume with memory	Running processes come back	partial Auto-sleep stops compute and wakes on the next request; files are kept, and in-memory state usually survives a wake but is not guaranteed (a rebuild boots fresh).
Fork a sandbox	Copy-on-write disk copy that boots fresh	Backup and restore of instance data is documented; no fork is described.
HTTPS URL per port	Private with a token, or public	Authenticated URL by default; public ports can be exposed.
Longest session	No limit on paid plans Auto-stop is up to 30 days or off	no stated limit Page says nothing times out mid-task.
Billing	Per second, flat rate per size Stopped sandboxes are free	per minute, vCPU + RAM + disk Compute stops on sleep; disk billed while retained.
GPUs
Self-host or open source
Regions	US East (Virginia) and EU Central (Finland)	us, eu (France), ap-south (Mumbai) Outside the US, VMs are the only instance type.

= not documented publicly.

Price for one 4 vCPU, 8 GB machine

Sandboxer

$0.036/hour

Flat per-second rate for the default size

Agent37

$0.012/hour

4 vCPU × $0.0011/h + 8 GB × $0.00096/h (standard gVisor shape, excludes disk; VM type is 2.5x compute)

List prices from each provider's pricing page, before free credits, plans and storage. This compares price only.

Where Agent37 is strong

Very low metered compute prices.
Sandboxes persist files across sleep and restarts with automatic backups.
Choice of gVisor sandboxes or full VMs with own kernel.
SOC 2 Type I, with Type II in progress.

Where Sandboxer differs

Standard Agent37 sandboxes use gVisor on shared hosts rather than a dedicated microVM kernel.
Agent37 bundles model access and integrations; Sandboxer provides preinstalled coding agents and a prompt API.
Agent37 offers /dev/kvm only on its VM instance type and does not state GPU support; every Sandboxer sandbox is a VM with nested KVM.

Pick Agent37 if

Cost is the main constraint and you want always-on agent hosting.
You want managed model access and app integrations bundled.
You want a white-label API for per-user agents.
You need a region in the EU (France) or India (Mumbai).

Pick Sandboxer if

You want every sandbox to be a full Ubuntu 24.04 VM with root, systemd, Docker and nested KVM by default, not a gVisor sandbox.
You want coding agents preinstalled in every sandbox and driven through a prompt API with streamed events.
You want a fixed per-size hourly price (default 4 vCPU/8 GB at $0.036/h) with plan dollars returned as machine time.

Sources

Products change. If something here is out of date, email hello@sandboxer.com and we'll fix it. Agent37 is a trademark of its owner. Sandboxer is an independent product and is not affiliated with Agent37.

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