Comparison · 2026

The best AI agent sandboxes in 2026

An AI agent sandbox is an isolated environment where an agent can run generated code, edit files, and call tools — safely, off your laptop. This is an honest comparison of the leading options by the things that actually decide the choice: self-hosting, persistence, isolation, license, MCP support, and cost.

Disclosure: we build Containarium, so we're biased — and we've tried to earn your trust by being specific about exactly when each alternative is the better choice. Where a competitor wins, we say so.

How we compared them

Six dimensions decide most agent-sandbox choices:

At a glance

Tool Best for License Self-host Persistence MCP
Containarium Self-hosted, persistent per-agent boxes Apache 2.0 First-class Persistent Native (in-box)
E2B Code-interpreter pattern via SDK Apache 2.0 Heavyweight Ephemeral (≤24h) Add-on server
Modal Serverless GPU scale, Python ML Proprietary None (hosted-only) Ephemeral Community only
Daytona Fork / branch parallel agent runs AGPL-3.0 Yes (cloud-first) Stateful + snapshots Orchestration server

Verified 2026. Competitor specifics change — check each project's current docs before deciding.

1.

Containarium

Best for: a self-hosted, persistent box per agent — with a permissive license.

Containarium gives each agent a real, persistent Linux box (an LXC container) on infrastructure you own, driven by an in-box MCP server and a CLI. It's Apache 2.0, ships a sentinel for routable hostnames + TLS, supports optional eBPF per-tenant network isolation, and does GPU passthrough on your own hardware. A hosted option (Containarium Cloud) exists when you'd rather not run ops.

Strengths

  • Self-host-first, Apache 2.0 — no copyleft, no vendor lock-in
  • Persistent box the agent lives in across sessions
  • MCP-native + bring-your-own-agent (Claude Code, Cursor, Cline)
  • eBPF network policy + GPU on your own hardware

Trade-offs

  • OSS core is single-host; multi-tenancy is the cloud product
  • Newer project — smaller ecosystem than incumbents
  • Not built for instant 1000-way serverless burst (see Modal)
Learn more about the agent sandbox
2.

E2B

Best for: the code-interpreter pattern, driven from your app via an SDK.

E2B is an Apache-2.0, SDK-first sandbox built around running AI-generated code. Sandboxes run on Firecracker microVMs with fast boot, and there's a strong Python/JS developer experience. If your product generates code and executes it per call, E2B fits that loop directly.

Strengths

  • Apache 2.0; mature code-interpreter SDK
  • Firecracker microVM isolation, fast cold start
  • Hosted cloud with a free starting tier

Trade-offs

  • Ephemeral by default (≤24h cap); persistence is beta
  • Self-hosting is heavyweight (GCP/Nomad/KVM)
  • SDK-first; MCP is a secondary add-on
Full comparison: Containarium vs E2B
3.

Modal

Best for: serverless scale and managed GPUs, in a Python-centric stack.

Modal is a hosted serverless AI-compute platform; its Sandboxes product runs agent code in gVisor-isolated containers that scale to zero and burst to high concurrency. It's an official sandbox provider for the OpenAI Agents SDK and excels when you need managed GPUs on demand without owning hardware.

Strengths

  • Serverless autoscale, scale-to-zero, huge concurrency
  • Managed GPUs on demand; strong Python DX
  • Polished observability and tooling

Trade-offs

  • Proprietary and hosted-only — no self-host / on-prem
  • Ephemeral sandboxes; Python-centric lock-in
  • No first-party MCP server; per-second cost compounds
Full comparison: Containarium vs Modal
4.

Daytona

Best for: fork / branch / snapshot-mid-execution parallel agent runs.

Daytona repositioned in 2025 into an agent runtime for running AI-generated code, with very fast sandbox creation and a standout fork/branch model — clone a running sandbox into many parallel branches and keep the winner. It ships SDKs in several languages and a first-class MCP server.

Strengths

  • Fork/branch + snapshot-mid-execution for fan-out
  • Fast sandbox creation; multi-language SDKs
  • First-class MCP orchestration server

Trade-offs

  • AGPL-3.0 — network-copyleft, a hurdle for some teams
  • Metered hosted cloud is the primary path
  • MCP is orchestration-layer, not in-box shell/files
Full comparison: Containarium vs Daytona

How to choose

↳ Need to keep code on your own infra, or want a permissive license? Containarium (Apache 2.0, self-host-first). Modal can't self-host; Daytona is AGPL.

↳ Building a code-interpreter where your app generates and runs code? E2B's SDK is built for exactly that.

↳ Need serverless burst to many GPUs without owning hardware? Modal.

↳ Fanning out one agent into many parallel branches? Daytona's fork/branch model.

↳ Want a durable box an agent lives in, driven by MCP? Containarium.

Give your agent a real box.

Self-host the open source on your VM, or start free on the hosted cloud.

Try Containarium Cloud How the agent sandbox works