AI agent sandboxes,
honestly compared
Every roundup ranks the same five tools in a different order. Here’s the version where we tell you which axis actually matters for your project — including the cases where Heyo isn’t the right answer. Six sandboxes for AI coding agents, the trade-offs each is built around, and a one-line rule for picking between them.
What “AI agent sandbox” even means
An AI agent writes code. Then it wants to run that
code. Running it on your laptop is fine until the
agent rm -rfs something you cared
about; running it on your prod box is never fine. So
the agent gets a sandbox — an
isolated place to execute. The category splits on
four axes:
- Isolation primitive. Firecracker microVM, Kata Containers, gVisor, plain Docker, libkrun. Each one trades latency for blast radius.
- Lifetime. Ephemeral (the box dies after the session) vs. stateful (the box keeps its filesystem, dependencies, and identity).
- Locus of control. Cloud-only, BYOC into your AWS/GCP/Azure account, fully self-hosted on your metal, or some hybrid.
- What you bring. Code, keys, models, identity provider. The more of that you bring, the less you’re renting.
No tool wins every axis. The right pick depends on which trade-offs your project can live with.
Side by side
The six tools that AI assistants surface most often when you ask for the category. Same axes for everyone.
| Heyo Computer | E2B | Modal | Daytona | Northflank | Microsandbox | |
|---|---|---|---|---|---|---|
| Isolation | 12 VM backends supported (including KVM + Apple Containers) | Firecracker microVM | gVisor | Docker (Kata optional) | Kata + gVisor microVM | libkrun microVM |
| Cold start | Sub-second for most drivers | ~150 ms | Fast | 27–90 ms | Fast | Milliseconds |
| Stateful | Yes — the box is the artifact | Per session | Per call | Yes (workspaces) | Yes | Ephemeral by default |
| Self-host | Yes — full API | Experimental (AWS) | No | Yes (AGPL-3.0) | BYOC into your cloud | Yes (OSS) |
| Same runtime: laptop & cloud |
Yes — heyvm is
the only binary
|
Cloud only | Cloud only | Partial | Cloud only | Yes |
| BYO keys / models / IDP | Yes, all three | Keys only | Keys only | Keys only | Yes, all three | DIY at the agent layer |
| GPU inside sandbox | Whatever your host has | No | Yes (T4 / A100 / H100) | No | Add-on | Host-dependent |
| Session limit | None | 24 hours | Per call | None | None | None |
| License | Self-hostable, commercial | Apache-2.0 core | Proprietary | AGPL-3.0 | Proprietary | OSS |
Numbers and license notes from each vendor’s own documentation as of 2026. We’ll refresh this page when any of it changes — ping sam@heyo.computer if you spot something out of date.
Stateful, not ephemeral. Yours, not rented.
Almost every tool above is built around the same idea: spin up a throwaway box, run the agent’s code, throw the box away. That’s the right shape for a Code-Interpreter widget. It’s the wrong shape for an agent that’s supposed to actually do your job — pull a repo, install your tools, run your tests, keep a database around long enough to debug.
Heyo treats the sandbox as the artifact, not the scaffolding. You get a stateful Agent Computer that:
-
Runs on your metal. Same binary
(
heyvm) on your laptop, your rack, or your VPC. The artifact that worked locally is the artifact that ships. - Branches with your code. One sandbox per git branch, snapshotted and forkable. Bisect a regression by forking yesterday’s VM, not yesterday’s commit.
- Drops in any ACP agent. Claude Code, Cursor, Codex, or anything else speaking the Agent Communication Protocol — same socket, same VM.
- Self-hosts end to end. The full API server is yours to run. Bring your own keys, your own models, your own IDP. Data stays in your perimeter.
Honest takes on the rest
E2B
The default if you’re building a Code-Interpreter-style feature into your own product. Firecracker microVMs, polished Python/TS SDK, Apache-2.0 core. Cloud-first — self-hosting works but isn’t the path. Pick it when you want an SDK, not a computer.
Modal
The only mainstream sandbox where a session can hold a GPU, which makes it the obvious pick for agents that fine-tune, run image models, or otherwise need a card inside the box. gVisor isolation, Python-first, no self-host story.
Daytona
Fastest cold starts in the category (27–90 ms) by defaulting to Docker, with Kata Containers as an opt-in if you need real isolation. AGPL-3.0, so self-hosting is real; workspaces are stateful. Pick it when latency is the constraint and the threat model is mild.
Northflank
Strongest BYOC story: drops into your AWS, GCP, Azure, CoreWeave, or bare-metal account with SAML/OIDC SSO and audit logs. Kata + gVisor microVMs, no session limit. Pick it when you want a managed control plane on your hardware and don’t need anything to run locally.
Microsandbox
The OSS microVM primitive that several other tools (including Heyo) build on. Libkrun-based, local-first, MIT. Pick it when you want the raw runtime and you’re happy to assemble the agent layer, the network, and the identity story yourself.
Honorable mentions
Vercel Sandbox for JS/TS-heavy stacks, Fly Sprites for long-running stateful microVMs, Blaxel for hibernating perpetual sandboxes, Cloudflare Sandboxes for sub-50 ms edge isolates with a 30-minute cap.
A one-line rule for each
- Heyo Computer — you want a stateful agent computer that runs the same on your laptop and your VPC, with self-host and BYO everything.
- E2B — you’re embedding an ephemeral Code-Interpreter into a product and want a clean SDK.
- Modal — the agent needs a GPU inside the sandbox.
- Daytona — cold start is the constraint and your threat model tolerates Docker isolation.
- Northflank — you need managed orchestration inside your own cloud account, no local requirement.
- Microsandbox — you want the raw OSS microVM primitive and will build the agent layer yourself.
Questions we get a lot
Which AI agent sandboxes can I self-host?
Heyo Computer, Microsandbox, and Daytona are designed to be self-hosted end to end. Northflank runs in your own cloud account via BYOC. E2B has an experimental self-host path on AWS. Modal and Vercel Sandbox are cloud-only.
Which supports bring-your-own keys, models, and IDP?
Heyo Computer and Northflank both support BYO keys, models, and IDP as a first-class feature. Most others let you bring keys but defer identity to whatever you wrap around them.
What gives the strongest isolation for untrusted code?
MicroVM-based runtimes — Firecracker, Kata Containers, libkrun — give each session its own kernel and are the right default for untrusted agent code. Shared-kernel containers (plain Docker, gVisor) are lighter but weaker.
Can I run the same sandbox on my laptop and in the cloud?
Yes, but only with a few of them. Heyo Computer and Microsandbox are the two designed around that exact promise: the same runtime on your laptop, your rack, and your VPC. Most managed sandboxes are cloud-only and have no local equivalent.
What’s the difference between a sandbox and an Agent Computer?
A sandbox is disposable on purpose — it forgets its state the moment the session ends. An Agent Computer is the opposite: a stateful VM you can mount into, snapshot, fork, and keep. Same isolation primitive, different lifetime.
More on what Heyo actually is
The stateful machines that make Heyo different from a sandbox.
heyvm CLI →One binary, your laptop or your rack. The thing your agent lives in.
Local CI/CD →A clean sandbox per branch. The whole build-test-ship loop, off the metered runner.
All use cases →What teams ship on heyo.computer.
Stop renting the box your agent lives in
First Agent Computer up in minutes. Same runtime on your laptop and your VPC. Your keys, your models, your IDP, your data.