Editorial status: This is a source-researched comparison, not a hands-on benchmark. The table includes only capabilities we could verify in first-party documentation on August 24, 2026. Vendor startup-time claims are not compared because the test conditions are not equivalent. Affiliate availability does not affect the comparison.

AI agents that execute generated code need more than a container-shaped API. They need a boundary that limits the damage from a malicious package, prompt injection, runaway process, or leaked credential.

For this guide, we evaluated four serious options: Daytona, Cloudflare Sandbox SDK, E2B, and Modal Sandboxes. They overlap, but they are not interchangeable. Daytona emphasizes persistent agent computers, Cloudflare integrates isolated execution with Workers, E2B offers a focused agent-native developer experience, and Modal brings sandboxes into a broader compute platform with strong resource controls.

The comparison at a glance

  • Daytona emphasizes persistent agent computers, multiple runtime classes, outbound controls, and broad SDK support.
  • Cloudflare Sandbox SDK combines separate VMs per sandbox with Workers-based outbound credential handling. It requires the Workers Paid plan and is still approaching a 1.0 stable release.
  • E2B emphasizes an agent-native API, custom templates, framework integrations, and transparent entry-level pricing.
  • Modal Sandboxes combines granular compute billing, resource caps, volumes, and network restrictions with Modal’s wider compute platform.

There is no universal winner. The right choice changes depending on whether your primary constraint is security policy, stateful long-running work, integration speed, or compute flexibility.

How we structured the comparison

We used five evidence categories defined before reviewing the products. We intentionally do not collapse them into a single score because different workloads require different tradeoffs.

Category Questions we asked
Security controls Is tenant isolation documented? Can outbound access and credentials be constrained? Are resource boundaries and customer responsibilities explicit?
Agent workflow Which SDKs, file/process APIs, templates, terminals, and preview mechanisms are documented?
State and lifecycle What survives stop, pause, sleep, snapshot, and deletion? Are volumes or external persistence available?
Cost transparency Are rates, billing units, entry costs, and plan limits public and understandable?
Deployment and portability Which regions, runtime choices, private deployment options, and adjacent platform services are available?

An undocumented capability received no credit. We also avoided awarding points for vendor-reported startup times, customer-logo counts, GitHub stars, or affiliate programs. Those measures are either difficult to compare fairly or unrelated to whether a sandbox fits a production workload.

Feature matrix

Product Isolation documented Outbound controls Persistent-state options Client SDKs noted here Public pricing style
Daytona Containers plus Linux/Windows VM options Block-all, domain/CIDR allowlists, proxy Stop/start, pause/resume, snapshots, forks, volumes Python, TypeScript, Ruby, Go, Java Usage model public; simple universal rate card not found in reviewed docs
Cloudflare Sandbox SDK Separate VM per sandbox Block, allow, intercept; Worker-side credential injection Active-container state; backup/restore and S3-compatible mounts TypeScript/Workers API Workers Paid plus published Containers rates
Modal Sandboxes gVisor default; VM runtime in beta Block-all, CIDR, beta domain allowlist Volumes and snapshots; some V2 features still developing Python, TypeScript, Go Public per-second CPU and memory rates
E2B Firecracker microVMs per vendor documentation Not documented as completely in the public pages reviewed Templates and session-bound state Python, TypeScript Free Hobby entry plus public per-second rates; paid base plans

An undocumented cell does not prove that a provider lacks the feature. It means buyers should verify the requirement directly before relying on it.

Daytona

Daytona’s current documentation covers a broad agent-computer lifecycle.

The default runtime is a Linux container, while Linux VM, Windows, and GPU sandbox classes are also documented. Daytona says each sandbox receives an isolated kernel, filesystem, network stack, and allocated compute resources. Its architecture documentation adds an important qualification: container sandboxes use isolated Linux namespaces, while VM sandboxes provide a distinct VM runtime. Buyers should choose the runtime based on their threat model rather than treating every Daytona sandbox class as identical.

The strongest differentiators are network and credential controls. Daytona documents per-sandbox domain and CIDR allowlists, a block-all mode, and an outbound proxy. Its secret system injects an opaque placeholder into the sandbox and substitutes the real credential only in HTTPS headers sent to approved hosts. The plaintext secret therefore does not need to exist in the sandbox environment or filesystem.

Daytona also has the richest state model in this comparison. Depending on sandbox class, it supports persistent filesystems, pause/resume, cold and hot snapshots, forks, and S3-backed volumes. Its Python, TypeScript, Ruby, Go, and Java SDKs reduce language lock-in at the client layer, and custom regions or bring-your-own compute expand deployment options.

Tradeoffs to verify

Its billing model is documented—reserved vCPU, RAM, and disk are charged according to lifecycle state—but the public documentation we reviewed did not present a simple universal rate card comparable to E2B or Modal. Some network capabilities also depend on the organization’s tier.

Daytona disclosed and patched an April 2026 credential-exposure vulnerability involving credentials held in sandbox process memory and passwordless sudo in the default snapshot. That disclosure is useful evidence of response transparency, but it is also a reminder to verify your snapshot, privilege, and credential model rather than relying on the word “sandbox.”

Choose Daytona when: you need persistent agent workspaces, multiple runtime classes, strong lifecycle operations, or a path to private/custom infrastructure.

Cloudflare Sandbox SDK

Cloudflare’s documentation is unusually explicit about both platform guarantees and customer responsibilities.

According to Cloudflare, every sandbox runs in a separate VM with filesystem, process, and network isolation plus per-sandbox resource limits. The documentation also warns that sandbox IDs are not cryptographic authentication and that customers must implement authentication, authorization, input validation, and rate limiting themselves.

The standout feature is outbound handling. A Worker can keep a real credential outside the sandbox and inject it into an approved outbound request. The same pattern is available for S3-compatible mounts through credential proxying, which prevents storage credentials from being written to container disk. This is stronger than simply placing a long-lived API key in an environment variable that untrusted code can read.

Cloudflare’s main tradeoff is lifecycle state. The stable SDK keeps files and processes while a container is active, but an idle container stops after 10 minutes by default and starts fresh on the next request. Persistent data requires explicit backup/restore or mounted object storage. That design can be a security benefit for ephemeral work, but it is less convenient than Daytona’s persistent-by-default model.

Pricing is tied to Cloudflare Containers and requires the $5-per-month Workers Paid plan. Published rates cover provisioned memory and disk, active CPU time, and regional egress. The platform integrates naturally with Workers, Durable Objects, R2, logs, and Cloudflare’s global network.

The current documentation also says Sandbox SDK 1.0 is available as a preview and recommends it for new projects. Teams with strict change-control requirements should account for that maturity stage.

Choose Cloudflare when: your application already runs on Workers, credential isolation matters more than persistent local state, or you want sandbox execution close to Cloudflare’s edge platform.

Modal is oriented toward teams that see agent sandboxes as part of a larger compute and machine-learning platform.

Its default sandbox runtime uses gVisor, while a full VM runtime with a real Linux kernel is available in beta. Modal documents block-all outbound networking, CIDR allowlists, and a beta domain allowlist. Incoming connections are disabled by default, and authenticated access can be added through connect tokens and tunnels.

Resource controls are particularly clear. Developers can set CPU and memory requests plus upper limits, helping contain a runaway or adversarial job. Billing is per second, with public CPU and memory rates, and Sandboxes can use Modal Volumes for durable data. The wider platform also provides GPU compute, although the current V2 Sandbox documentation lists GPUs as not yet supported for that V2 path and the VM Sandbox beta does not support GPUs. Confirm the exact runtime path before designing around GPU execution.

Modal supports Python, JavaScript/TypeScript, and Go clients. That is enough for many teams but narrower than Daytona’s documented SDK set. Several advanced V2 capabilities remain marked active-development, beta, or experimental, so teams should verify their maturity against production requirements.

Choose Modal when: sandbox jobs need granular compute controls, shared volumes, data workflows, or proximity to a broader serverless ML platform.

E2B

E2B is the most focused product in this comparison. Its API and documentation are designed around giving AI agents a Linux computer, and its templates can preinstall dependencies and snapshot a running start command so new environments arrive ready for work.

E2B says its sandboxes use Firecracker microVMs and can run code for many agent frameworks and model providers. It has direct relevance to coding agents, computer-use workflows, data analysis, and artifact generation. The free Hobby plan includes usage credits, up to 20 concurrent sandboxes, and sessions up to one hour. Pro currently lists a $150 monthly platform fee plus usage, up to 100 concurrent sandboxes, and sessions up to 24 hours. CPU and memory rates are published per second.

E2B’s narrow product focus may reduce integration work. The public first-party pages we reviewed did not document outbound domain/CIDR policy and external credential-brokering controls as completely as Daytona, Cloudflare, or Modal. We do not infer the absence of a feature from missing documentation; buyers should verify these controls directly when they matter.

State is primarily bounded by sandbox session lifetime and templates rather than the multi-state persistence model documented by Daytona. Enterprise options include private-cloud or self-hosted deployment, but public details and pricing require sales contact.

Choose E2B when: you want the shortest path from an agent framework to an isolated Linux environment and your required controls are covered by E2B’s documented plan or an enterprise agreement.

Security questions to ask every sandbox provider

The product name matters less than how you configure it. Before adopting any provider, answer these questions:

  1. Is every tenant or user placed in a separate sandbox, VM, or equivalent hard boundary?
  2. Is outbound internet access blocked by default, allowlisted, or unrestricted?
  3. Can untrusted code read production credentials from environment variables, files, process memory, or metadata endpoints?
  4. Can credentials be injected outside the sandbox only for approved hosts and requests?
  5. What survives stop, pause, sleep, snapshot, and deletion?
  6. Which limits cap CPU, memory, disk, runtime, network egress, and concurrent creation?
  7. Are preview URLs authenticated, or are they possession-based public URLs?
  8. What logs are available for commands, network activity, lifecycle events, and administrative actions?
  9. Which features depend on a higher tier, beta runtime, or private agreement?
  10. How quickly can you revoke a sandbox, credential, snapshot, or tenant after compromise?

How to choose

Choose based on the constraint you cannot compromise. Daytona documents the broadest persistence and runtime menu. Cloudflare fits naturally into a Workers architecture and documents strong external credential-handling patterns. E2B offers a focused agent-first interface. Modal connects sandbox execution to a wider compute and ML platform. None is automatically superior for every workload.

Treat this guide as a shortlist, not a substitute for a proof of concept. Before production adoption, run the same workload on your finalists and measure cold start, steady-state latency, failure recovery, egress enforcement, credential exposure, filesystem behavior, and total cost under your own concurrency pattern.

Sources and verification notes

This comparison was fact-checked against first-party documentation on August 24, 2026. Relevant sources include:

Product capabilities and prices can change. Recheck the linked provider pages before making a purchase or architecture decision.