- For teams whose agents write and run their own code
- Questions that separate an agent sandbox from a dev environment
- E2B alternatives compared
- Twelve options, in no particular order
- Where the sandbox fits in your agent stack
- Choosing a provider is half the security job
- Advice for picking an agent sandbox
- Frequently asked questions
If your AI agent writes code and runs it, the E2B alternative you want is the one that keeps that code isolated, starts fast enough for your agent's loop and gives you clear control over what it can reach. Some options here are true agent sandboxes and some are developer environments, so check which kind you're looking at.
For teams whose agents write and run their own code
An agent that can run code is far more useful than one that can only talk about it. It's also a little scary. The code is written by a model, nobody's reviewed it, and it might try to read files, call the network or loop forever. Teams building agents like that look at E2B because they need somewhere safe to run it, and they compare alternatives when they want a different speed, setup or level of control.
That's the buyer for this list. If you're a developer who simply wants a nicer browser IDE, a couple of tools here will suit you too, but the questions below are written for agent builders.
Questions that separate an agent sandbox from a dev environment
- How is the code isolated: a microVM, a virtual machine, a container or a browser tab?
- How long does a fresh environment take to start, and can it pause and resume?
- Can you limit network access and the files the agent can see?
- Can you branch or snapshot an environment so an agent can try two paths?
- Do you need it self-hosted inside your own infrastructure, or is a hosted service fine?
- What logs and audit trail do you get when something goes wrong?
Answer those and the list sorts itself. The microVM-style sandboxes are built for untrusted code. The cloud development platforms are built for people writing code, and they're a better fit when a human stays in the loop.
E2B alternatives compared
| Tool | Product type | Good for |
|---|---|---|
| Blaxel | Agent infrastructure | Fast-booting microVMs with programmable networking |
| Cloudflare Sandbox | Code execution sandbox | Untrusted code in VMs or isolated Workers |
| Coder | Self-hosted dev environments | Governed environments for AI coding agents |
| CodeSandbox | Cloud development platform | Coding and collaborating from any device |
| Daytona | AI code runtime | Deploying and running AI-generated code |
| Gitpod | Cloud agent platform | Teams of AI software engineers in the cloud |
| Modal | AI cloud infrastructure | Developing, training and serving AI apps |
| Morph | Agent infrastructure | Instant environment branching and burst scaling |
| Northflank | Execution layer | Running agents and what they generate |
| Runloop | Agent platform | Sandboxes, evaluations and production for agents |
| StackBlitz | Browser-based IDE | Web development with no local setup |
| Vercel Sandbox | Code execution sandbox | Agent code in isolated Linux microVMs |
Twelve options, in no particular order
Listed alphabetically, in no particular order. I've kept each line to what the vendor says the product is for.
Blaxel
Best for: Autonomous agents that need microVMs that the vendor says boot in milliseconds, with shared memory and programmable networking.
Cloudflare Sandbox
Best for: Executing untrusted or generated code inside Linux virtual machines or isolated Workers.
Coder
Best for: Companies that want self-hosted, governed environments for AI coding agents, with audit logging and permission controls.
CodeSandbox
Best for: Developers who want a cloud development platform to code, collaborate and ship from any device.
Daytona
Best for: Teams that want a dedicated place to deploy and run AI-generated code.
Gitpod
Best for: Running a team of AI software engineers in the cloud, with orchestration and governance built in.
Modal
Best for: Teams that develop, train and serve AI applications at scale on one cloud.
Morph
Best for: Agents that need to branch environments and burst to scale, which the vendor says happens in milliseconds.
Northflank
Best for: Hosting AI agents and everything they generate on one execution layer.
Runloop
Best for: Enterprise agent projects that move from secure sandboxes to evaluations and then production.
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StackBlitz
Best for: Web developers who want a collaborative browser-based IDE with no local configuration.
Vercel Sandbox
Best for: Running untrusted or agent-generated code in isolated Linux microVMs.
Where the sandbox fits in your agent stack
A sandbox is one piece of a bigger loop. The model plans, writes code, hands it to the sandbox, reads the output and decides what to do next. That loop runs many times per task, so a sandbox that's slow to start or hard to reset slows the whole agent down. It's worth measuring the full round trip, not just the boot time on a vendor's homepage, and keeping your sandbox calls behind one small wrapper so you can swap providers without rewriting the agent.
If you're building the agent itself, my guide to the Claude Agent SDK shows how agents call tools such as a code runner, and my piece on Copilot agent mode covers the coding-assistant side.
Choosing a provider is half the security job
It's tempting to think a sandbox makes you safe by default. The UK NCSC's cloud security principles make a useful point here: they're designed to help you choose a provider that meets your security needs, and you'll separately need to think about how you configure it. For agent code, that second half means network rules, secrets, timeouts and who can see the logs.
Do you make an AI code sandbox or agent runtime? Tool makers can ask to be considered for a featured place on this list.
Advice for picking an agent sandbox
Write one nasty test task for your agent, such as code that tries to read environment variables and call an outside URL, and run it on two or three sandboxes. See what's blocked, what's logged and how quickly a fresh environment comes up. That one test tells you more than a week of reading docs, and it's the test your security-minded customers will ask about anyway.
Want your tool on this list? Featured spots and reviews here are paid partnerships. Here's how to partner with me.
Frequently asked questions
What is an AI code sandbox?
It's an isolated environment where code written by an AI model can run without touching your main systems. Good sandboxes limit what the code can reach, start quickly and can be thrown away after each task.
Is a cloud IDE the same as an agent sandbox?
Not quite. A cloud IDE is built for a person writing code, with an editor and collaboration features. An agent sandbox is built for code no human has reviewed, so isolation, speed and automation matter more.
Should I self-host my agent sandboxes?
Self-hosting gives you the most control over data and permissions, which some regulated teams need. A hosted service is quicker to start with. Pick based on where your data is allowed to live.
What's a microVM and why does it matter?
A microVM is a very small virtual machine that boots quickly but keeps stronger isolation than a plain container. It's a common choice for running untrusted code because it separates each task more cleanly.
Are these E2B alternatives ranked?
No. They're in alphabetical order and in no particular order. The right one depends on how your agent runs code and how much control you need.
