Best Modal Sandboxes alternatives in 2026, ranked (for sandboxes, not GPUs)

Short answer: For sandbox use rather than GPU work, we rank Sandboxer first, then Freestyle and E2B: each gives a sandbox its own VM kernel instead of Modal's default gVisor, and keeps memory across pauses. Pick Northflank for GPUs in your own cloud, Vercel Sandbox for apps on Vercel, and stay on Modal for GPUs or very large numbers of short jobs.

Published by Sandboxer, and we're on this list. We ranked by the criteria below and say where others, including Modal, are the better choice. Every fact about another platform comes from its own docs or pricing page, checked on the date shown; follow each name for the full comparison and sources.

What Modal Sandboxes are, and when to look elsewhere#

Modal's sandboxes run on its serverless platform: gVisor isolation by default, GPUs available, raw TCP tunnels as well as HTTPS ports, and SDKs for Python, JavaScript and Go. Modal says it can start a million sandboxes in under a minute. Our full side-by-side is at Sandboxer vs Modal.

This page is for teams using Modal Sandboxes as sandboxes: agent workspaces, code execution, preview environments. Reasons to compare:

• you want a VM with its own kernel on every sandbox rather than gVisor;
• you need running processes to survive a pause;
• you want a full machine: root, systemd and Docker;
• you want sandboxes that live for hours or days.

When to stay on Modal: for GPUs in sandboxes, or very large numbers of short jobs on the platform you already use.

How to compare the alternatives#

1. Isolation: a microVM or VM with its own kernel.
2. Pause with memory: running processes survive a pause.
3. A full machine: root, systemd and Docker.
4. Session length: no short platform cap.
5. Price: the list price for a 4 vCPU, 8 GB machine-hour.

We apply the criteria in this order; later ones break ties.

Comparison table#

"Not documented" means the platform's public docs don't say. Prices are list prices for one 4 vCPU, 8 GB machine-hour; a dash means the platform doesn't sell that size by the hour or doesn't publish a price for it.

The alternatives, ranked#

1. Sandboxer#

At a glance (source: our docs and pricing): isolation: microVM (Cloud Hypervisor, its own kernel) · resume keeps processes: Yes · longest session: No limit on paid plans · price: $0.036/hour.

Best for: agent workspaces and long jobs on a whole machine. Each sandbox is a Cloud Hypervisor microVM with Ubuntu 24.04, root, systemd, Docker and /dev/kvm, coding agents preinstalled, and an HTTPS URL for any port. Stopping saves memory, and a stopped sandbox costs nothing.

Where Modal or others win: no GPUs and no SLA during early access; Modal also starts far larger numbers of short sandboxes.

2. Freestyle#

At a glance (source: Freestyle docs, checked 2026-10-24): isolation: full Linux VM (hypervisor not named) · resume keeps processes: Yes · longest session: no maximum stated · price: $0.26/hour · full comparison and sources.

Best for: live forking with SSH and domain routing; full Linux VMs with pause and resume that preserves memory; an Enterprise SLA and SAML/SCIM.

Where it's weaker for this use: persistent VMs need a paid plan, and the hypervisor isn't named in its docs.

3. E2B#

At a glance (source: E2B docs, checked 2026-10-15): isolation: microVM · resume keeps processes: Yes · longest session: see comparison · price: $0.33/hour · full comparison and sources.

Best for: open source and running in your own cloud. Firecracker microVMs whose pause keeps memory and processes, fork in one call, and Terraform for AWS or GCP.

Where it's weaker for this use: sessions are capped per plan.

4. Blaxel#

At a glance (source: Blaxel docs, checked 2026-10-24): isolation: microVM (hypervisor not named) · resume keeps processes: Yes · longest session: no fixed limit stated · price: $0.33/hour · full comparison and sources.

Best for: near-instant wake from standby on microVMs, with regions in the US and Europe.

Where it's weaker for this use: the hypervisor isn't named in its docs.

5. Northflank Sandboxes#

At a glance (source: Northflank Sandboxes docs, checked 2026-10-24): isolation: microVM on Cloud Hypervisor (gVisor for GPU sandboxes) · resume keeps processes: Not documented · longest session: no limit · price: $0.13/hour · full comparison and sources.

Best for: the closest fit if you need GPUs too: Cloud Hypervisor microVMs (gVisor for GPU workloads), sandboxes that run until you delete them, and bring-your-own-cloud.

Where it's weaker for this use: whether a pause keeps memory isn't documented.

6. Fly.io Sprites#

At a glance (source: Fly.io Sprites docs, checked 2026-10-24): isolation: microVM (hardware-isolated) · resume keeps processes: Partly · longest session: no maximum stated · price: $0.33/hour · full comparison and sources.

Best for: persistent microVMs with no compute charge while idle.

Where it's weaker for this use: after a longer idle period the in-memory state is dropped.

7. Daytona#

At a glance (source: Daytona docs, checked 2026-10-15): isolation: container or VM · resume keeps processes: Partly · longest session: see comparison · price: $0.33/hour · full comparison and sources.

Best for: Windows sandboxes, GPUs, and SDKs in Ruby and Java. VM sandboxes can pause with memory preserved.

Where it's weaker for this use: VM isolation and memory-saving stop depend on the sandbox class.

8. Vercel Sandbox#

At a glance (source: Vercel Sandbox docs, checked 2026-10-15): isolation: microVM · resume keeps processes: No · longest session: see comparison · price: $0.68/hour · full comparison and sources.

Best for: apps on Vercel: Firecracker microVMs with active-CPU billing and many regions.

Where it's weaker for this use: resume doesn't keep running processes.

9. Cloudflare Sandbox#

At a glance (source: Cloudflare Sandbox docs, checked 2026-10-24): isolation: microVM per container instance (docs: each instance has its own kernel) · resume keeps processes: No · longest session: no fixed limit stated · price: $0.36/hour · full comparison and sources.

Best for: short, event-driven sandboxes from Cloudflare Workers, each container instance in its own microVM.

Where it's weaker for this use: no resume with memory.

10. Runloop#

At a glance (source: Runloop docs, checked 2026-10-24): isolation: VM (technology not named) · resume keeps processes: Partly · longest session: Not documented · price: $0.63/hour · full comparison and sources.

Best for: agent evaluation with blueprint-based environments, and VPC deployment on Enterprise.

Where it's weaker for this use: suspend and resume need the Pro plan, the docs don't say whether memory is kept, and the VM technology isn't named.