Comparison · Updated September 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 nine 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. We list ourselves first; the rest are numbered for navigation, not ranked.

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 Runs ≤24h; pause keeps state Add-on server
Modal Serverless scale and managed GPUs Proprietary None (hosted-only) ≤24h; filesystem snapshots SDK-driven
Runloop Managed microVM devboxes, agent evals Proprietary VPC (Enterprise) Suspend/resume (disk) MCP Hub
Sprites Hosted persistent computer per agent Proprietary None (Fly.io) Persistent + checkpoints Agent plugins
Morph Cloud Snapshot and branch running VMs Proprietary None (hosted) Snapshots + branches SDK-driven
Docker Sandboxes Guarding your laptop from a coding agent Docker product Runs locally Disposable sessions Not built in
Daytona Hosted fork / branch agent runs AGPL-3.0 (frozen repo) Unmaintained since June 2026 Stateful + snapshots MCP server
agent-sandbox A Kubernetes primitive to build on Apache 2.0 Your K8s cluster Stateful pod Not built in

Checked against each vendor's public docs and pricing pages in September 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 or a Kubernetes pod) 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 egress policy, 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; works with Claude Code, Cursor, Codex, Gemini CLI, Goose
  • eBPF egress policy + GPU on your own hardware

Trade-offs

  • Shared-kernel containers — a weaker boundary than a microVM for hostile code
  • 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
  • Paused sandboxes keep their state indefinitely

Trade-offs

  • 5-minute default timeout; a running sandbox is capped at 1h (Hobby) / 24h (Pro)
  • Self-hosting is heavyweight
  • SDK-first; MCP is a secondary add-on
Full comparison: Containarium vs E2B
3.

Modal

Best for: serverless scale and managed GPUs.

Modal is a hosted serverless AI-compute platform; its Sandboxes run agent code in gVisor-isolated containers that scale to zero and burst to high concurrency, with SDKs for Python, JavaScript and Go. It excels when you need managed GPUs on demand without owning hardware.

Strengths

  • Serverless autoscale, scale-to-zero, huge concurrency
  • Managed GPUs on demand
  • Filesystem snapshots to carry state between sandboxes

Trade-offs

  • Proprietary and hosted-only — no self-host / on-prem
  • Sandboxes live 5 minutes by default, 24 hours at most
  • SDK-driven; per-second cost compounds on long-lived work
Full comparison: Containarium vs Modal
4.

Runloop

Best for: a managed microVM platform for coding agents, with evaluation tooling.

Runloop runs Devboxes — isolated Linux environments on microVMs — as a managed, SOC 2 Type II platform driven from Python and TypeScript SDKs. It adds tooling for benchmarking and fine-tuning agents on the same platform.

Strengths

  • MicroVM isolation between tenants
  • Suspend/resume; suspended devboxes bill storage only
  • Agent benchmarking and training tooling

Trade-offs

  • Suspend keeps disk, not memory
  • Self-hosting only as VPC deployment on Enterprise
  • Pro plan is $250/month plus usage
Full comparison: Containarium vs Runloop
5.

Sprites

Best for: a hosted persistent computer per agent, with nothing to run.

Sprites, from Fly.io, are persistent Linux computers for agents: durable storage, copy-on-write checkpoints in about a second, and a TLS URL per Sprite. Idle Sprites go warm, then cold, and stop billing compute.

Strengths

  • Persistent disk plus ~1 s checkpoints and restore
  • Idle computers stop billing compute
  • CLI, REST API, and SDKs (JS, Go, Python, Elixir)

Trade-offs

  • Hosted on Fly.io only — no self-host
  • No GPUs listed
  • Usage pricing per CPU-hour and GB-hour
Full comparison: Containarium vs Sprites
6.

Morph Cloud

Best for: branching one running state into many parallel attempts.

Morph Cloud's Infinibranch snapshots a running VM and forks or restores it in well under a second, which suits agent rollouts, search, and RL harnesses that restore the same state thousands of times.

Strengths

  • Snapshot, branch and restore VMs in ~250 ms or less
  • VM-level isolation
  • Near-zero storage overhead per branch

Trade-offs

  • Hosted service
  • Built around branching, not one long-lived box
  • Billed in Morph Compute Units
Full comparison: Containarium vs Morph Cloud
7.

Docker Sandboxes

Best for: letting a coding agent run unsupervised without risking your laptop.

Docker Sandboxes run Claude Code, Codex, Gemini CLI, Copilot CLI or Kiro inside a microVM with its own Docker daemon, so the agent can build containers without touching the host. Since September 2026 the same sandboxes also run in Docker's cloud.

Strengths

  • MicroVM isolation with a private Docker daemon
  • One command to sandbox a supported agent
  • Cloud option from $0.07/hr, billed per second

Trade-offs

  • Designed as disposable sessions (cloud sessions up to 24h)
  • No public hostname for what the agent builds
  • Limited to the agents it supports
Full comparison: Containarium vs Docker Sandboxes
8.

Daytona

Best for: hosted, fast-starting sandboxes with fork / branch.

Daytona is an agent runtime for AI-generated code with very fast sandbox creation, snapshots, SDKs in five languages and an MCP server. In June 2026 it moved core development to a private codebase; the public AGPL-3.0 repository no longer receives updates.

Strengths

  • Very fast sandbox creation
  • Snapshots and fork / branch for fan-out
  • SDKs for Python, TypeScript, Ruby, Go, Java

Trade-offs

  • Public repo unmaintained since June 2026 — self-hosting means a frozen fork
  • Last public release is AGPL-3.0
  • Metered hosted cloud is the supported path
Full comparison: Containarium vs Daytona
9.

kubernetes-sigs/agent-sandbox

Best for: building your own agent platform on Kubernetes.

agent-sandbox is the Kubernetes SIG Apps project that defines a Sandbox resource: one stateful pod with stable identity and storage, plus templates and warm pools. It's a primitive, not a product — Containarium's own Kubernetes backend is built on it.

Strengths

  • Apache 2.0, Kubernetes-native, v1.0 stable
  • Warm pools for fast allocation
  • Delegates isolation to gVisor or Kata Containers

Trade-offs

  • You build access, routing and multi-tenancy yourself
  • Clients typically need cluster access
  • No agent interface (MCP) built in
Full comparison: Containarium vs agent-sandbox

How to choose

↳ Need to keep code on your own infra, or want a permissive license? Containarium (Apache 2.0, self-host-first). On Kubernetes and building your own platform, agent-sandbox.

↳ 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 one agent state out into many parallel attempts? Morph Cloud's branching.

↳ Want a managed platform with microVM isolation and agent evals? Runloop.

↳ Want a persistent computer per agent with nothing to operate? Sprites.

↳ Just want a coding agent on your laptop to stop touching your host? Docker Sandboxes.

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

FAQ

What is an AI agent sandbox?

An AI agent sandbox is an isolated environment where an autonomous agent can run commands, execute generated code, edit files, and call tools without touching your machine or other tenants. Sandboxes differ in their isolation technology, whether the environment persists, whether you can self-host, the open-source license, and whether agents drive them over MCP or a language SDK.

Which AI agent sandbox can I self-host?

Containarium is self-host-first under Apache 2.0, with a single VM as the default path. kubernetes-sigs/agent-sandbox (Apache 2.0) runs on your own Kubernetes cluster, but it is a primitive rather than a finished product. E2B can be self-hosted, but the process is heavyweight. Runloop offers VPC deployment on its Enterprise plan. Daytona's public repository has not been maintained since June 2026. Modal, Sprites and Morph Cloud are hosted services. Docker Sandboxes run on your own machine or in Docker's cloud.

Which AI agent sandbox is best for running AI-generated code?

E2B is purpose-built for the code-interpreter pattern via its SDK; Modal is strong for serverless, scale-to-zero execution at high concurrency; Morph Cloud and Daytona suit fanning one state out into many parallel attempts; Containarium is best when you want a persistent, self-hosted box the agent works in over time.

Which AI agent sandboxes are persistent?

Containarium boxes and Sprites are long-lived computers that keep their disk between sessions. Runloop suspends devboxes to disk, E2B keeps paused sandboxes indefinitely, and Modal and Morph Cloud preserve state through snapshots. Docker Sandboxes are designed to be disposable.

Do AI agent sandboxes support MCP?

Support varies. Containarium is MCP-native: each box runs an MCP server with shell and file tools. Daytona ships an MCP server and Runloop has an MCP Hub. E2B offers MCP as an add-on to its SDK. Modal, Morph Cloud and agent-sandbox are driven through SDKs and APIs.

Keep reading

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