E2B vs Cloudflare Sandbox SDK
Answer in brief
Choose E2B for code interpreters and short-to-medium-lived agent tasks that need microVM isolation, with an open-source self-host path; choose Cloudflare Sandbox SDK for teams building on Cloudflare Workers that want per-user sandboxes with egress and credentials controlled in code. E2B uses Firecracker microVM isolation and is open source; Cloudflare Sandbox SDK uses MicroVM (Containers) isolation and is open source.
E2B vs Cloudflare Sandbox SDK at a glance
| Attribute | E2B | Cloudflare Sandbox SDK |
|---|---|---|
| What it is | Open-source cloud sandboxes for AI agents, each a Firecracker microVM, with pause/resume, snapshots and forking. | A TypeScript SDK for Cloudflare Workers that runs untrusted code in Linux sandboxes backed by Cloudflare Containers and Durable Objects. |
| Isolation | Firecracker microVM with its own kernel per sandbox | Each container instance is a microVM with its own kernel and network (per Cloudflare docs); Dynamic Workers (V8 isolates) available for JavaScript-only code |
| Open source | Yes (Apache-2.0) | Yes (SDK Apache-2.0 (runs only on Cloudflare)) |
| Self-host / BYOC | Yes / Yes | No / No |
| SDKs | Python, JavaScript/TypeScript | TypeScript (Workers) |
| Cold start (vendor claim) | Not documented | Container cold starts “often in the 1–3 second range” depending on image (vendor docs) |
| Max session | Up to 1 hour continuous (Hobby), 24 hours (Pro) or custom (Enterprise); pausing resets the clock and paused sandboxes are kept until deleted | No fixed cap; runs while its Durable Object is active, then up to a 6-hour inactivity timeout |
| Persistence | Pause/resume preserves filesystem and memory; snapshots of running sandboxes, forking from a snapshot, filesystem-only snapshots, auto-resume and volumes (beta) | Ephemeral disk by default; container snapshots (up to 20 GB, 30 days), directory backups to R2, S3/R2 bucket mounts and Durable Object storage |
| GPU | No — sandboxes are CPU-only | Not documented |
| Networking | Internet on by default; can be disabled or restricted with allow/deny lists of IPs, CIDRs and domains; public sandbox URLs for exposed ports; custom domains and published egress IPs | Egress controlled from Worker code: disable internet and intercept outbound HTTP to allow specific hosts and inject credentials; preview URLs routed through your Worker |
| Pricing | Per second: $0.000014 per vCPU-second (~$0.050/vCPU-hour) + $0.0000045 per GiB-second (~$0.016/GiB-hour). Pro plan $150/month plus usage; Enterprise from $3,000/month | Cloudflare Containers rates in 10 ms increments: $0.000020 per vCPU-second (active) + $0.0000025 per GiB-second + disk; requires the $5/month Workers Paid plan |
| Compliance | SOC 2 Type II; HIPAA BAA and DPA available on request | Not documented |
| Best for | Code interpreters and short-to-medium-lived agent tasks that need microVM isolation, with an open-source self-host path | Teams building on Cloudflare Workers that want per-user sandboxes with egress and credentials controlled in code |
Verified November 8, 2026 from each provider’s documentation. Cold-start figures are vendor claims, not our measurements.
Which should you choose?
Choose E2B if…
- You want the most widely integrated agent sandbox, with a large ecosystem of examples
- You need Firecracker microVM isolation for untrusted multi-tenant code
- You want an open-source codebase you can self-host or run via BYOC
- You want ready-made code-interpreter and desktop SDKs
Choose Cloudflare Sandbox SDK if…
- You build on Cloudflare Workers and Durable Objects
- You want egress and credentials controlled in your own code
- You want global placement on Cloudflare’s network
- You want a lighter isolate option for JS-only code
Both are worth piloting with your own image and region. See the full E2B profile and Cloudflare Sandbox SDK profile, or the complete comparison.
Frequently asked questions
Is E2B or Cloudflare Sandbox SDK better for AI agents?
Neither is better for every workload. E2B is best for code interpreters and short-to-medium-lived agent tasks that need microVM isolation, with an open-source self-host path. Cloudflare Sandbox SDK is best for teams building on Cloudflare Workers that want per-user sandboxes with egress and credentials controlled in code.
Which is open source, E2B or Cloudflare Sandbox SDK?
Both are open source (E2B: Apache-2.0; Cloudflare Sandbox SDK: SDK Apache-2.0 (runs only on Cloudflare)).
How do E2B and Cloudflare Sandbox SDK isolate code?
E2B: Firecracker microVM with its own kernel per sandbox. Cloudflare Sandbox SDK: Each container instance is a microVM with its own kernel and network (per Cloudflare docs); Dynamic Workers (V8 isolates) available for JavaScript-only code.
Sources
Cite this page
Agent Sandboxes. (2026). E2B vs Cloudflare Sandbox SDK. agentsandboxes.org. Last reviewed November 8, 2026. https://agentsandboxes.org/compare/e2b-vs-cloudflare-sandbox/
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