E2B vs Modal Sandboxes
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 Modal Sandboxes for high-concurrency and GPU-backed sandboxes — RL rollouts, evals and coding agents at scale. E2B uses Firecracker microVM isolation and is open source; Modal Sandboxes uses gVisor or VM isolation.
E2B vs Modal Sandboxes at a glance
| Attribute | E2B | Modal Sandboxes |
|---|---|---|
| What it is | Open-source cloud sandboxes for AI agents, each a Firecracker microVM, with pause/resume, snapshots and forking. | Sandboxes on Modal’s serverless compute platform for running untrusted code at very high scale, with GPUs, snapshots and tunnels. |
| Isolation | Firecracker microVM with its own kernel per sandbox | gVisor by default, or VMs with their own Linux kernel; GPU sandboxes use gVisor |
| Open source | Yes (Apache-2.0) | No (Client SDK Apache-2.0) |
| Self-host / BYOC | Yes / Yes | No / Not documented |
| SDKs | Python, JavaScript/TypeScript | Python, JavaScript/TypeScript, Go |
| Cold start (vendor claim) | Not documented | Sub-second, including for large custom images (vendor claim) |
| 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 | 5 minutes default, configurable up to 24 hours; snapshots carry state beyond that |
| Persistence | Pause/resume preserves filesystem and memory; snapshots of running sandboxes, forking from a snapshot, filesystem-only snapshots, auto-resume and volumes (beta) | Filesystem snapshots, directory snapshots, memory snapshots (alpha) and Modal Volumes |
| GPU | No — sandboxes are CPU-only | Yes — Modal’s full GPU range (T4 to B300) at standard per-second rates, e.g. H100 $0.001097/s |
| 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 | Outbound open by default; block all, CIDR allowlists or domain allowlists (beta), updatable at runtime; encrypted tunnels with public URLs and connect tokens |
| 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 | Per second at sandbox (non-preemptible) rates: $0.00003942 per physical core-second (1 core = 2 vCPU) + $0.00000667 per GiB-second; GPUs at standard rates. Team plan $250/month |
| Compliance | SOC 2 Type II; HIPAA BAA and DPA available on request | SOC 2 on all plans; HIPAA on Enterprise |
| Best for | Code interpreters and short-to-medium-lived agent tasks that need microVM isolation, with an open-source self-host path | High-concurrency and GPU-backed sandboxes — RL rollouts, evals and coding agents at scale |
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 Modal Sandboxes if…
- You need very high concurrency (RL, evals, batch agents)
- You need GPUs inside the sandbox
- You already use Modal for inference or training
- You want Go as well as Python and TypeScript SDKs
Both are worth piloting with your own image and region. See the full E2B profile and Modal Sandboxes profile, or the complete comparison.
Frequently asked questions
Is E2B or Modal Sandboxes 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. Modal Sandboxes is best for high-concurrency and GPU-backed sandboxes — RL rollouts, evals and coding agents at scale.
Which is open source, E2B or Modal Sandboxes?
E2B is open source (Apache-2.0); Modal Sandboxes is not.
How do E2B and Modal Sandboxes isolate code?
E2B: Firecracker microVM with its own kernel per sandbox. Modal Sandboxes: gVisor by default, or VMs with their own Linux kernel; GPU sandboxes use gVisor.
Sources
Cite this page
Agent Sandboxes. (2026). E2B vs Modal Sandboxes. agentsandboxes.org. Last reviewed November 8, 2026. https://agentsandboxes.org/compare/e2b-vs-modal/
Found an error or a missing sandbox? Submit a correction — every entry links to the sources it relies on.