Unikraft Cloud alternatives
The 6 alternatives below are grouped by kind of sandbox, and each says what it does differently from Unikraft Cloud. Start from whatever made you look: missing GPUs, session limits, self-hosting, pricing or isolation.
Why teams look beyond Unikraft Cloud
A density- and latency-focused microVM platform whose stateful forking and shielded egress suit large agent fleets, if you can work with unpublished pricing.
- No public pricing; hosted plans are contact-sales
- GPU support is an enterprise preview on a different (QEMU) instance type without branching or checkpoints
- The platform itself is proprietary; only the underlying Unikraft kernel project is open source
- Maximum instance sizes and session limits are not documented
Unikraft Cloud alternatives, by kind
Hosted sandbox platforms
SDK-driven sandboxes you create, run code in and destroy through an API.
Blaxel
Perpetual microVM sandboxes for AI agents that drop to standby when idle and resume with memory intact, plus volumes, batch jobs and MCP hosting.
- MicroVM
- BYOC
- Pause/resume
How it differs: Always-available agents that sit idle most of the time and need near-instant resume. A strong design for always-on, mostly-idle agents; watch how the Baseten acquisition shapes the roadmap.
E2B
Open-source cloud sandboxes for AI agents, each a Firecracker microVM, with pause/resume, snapshots and forking.
- Firecracker microVM
- Open source
- Self-hostable
- BYOC
- Pause/resume
How it differs: Code interpreters and short-to-medium-lived agent tasks that need microVM isolation, with an open-source self-host path. The safe default for most agent builders: mature, open source, microVM-isolated and widely supported.
Persistent VMs and agent computers
Full, long-lived virtual machines that an agent keeps, forks and returns to.
Morph Cloud
VM-based cloud computers for AI agents built on “Infinibranch” snapshot, branch and restore, plus persistent Devboxes.
- VM
- Pause/resume
How it differs: Workloads that branch a running environment many times — parallel search, RL and evaluation rollouts. Purpose-built for branching workloads; a specialist pick for search, RL and evals.
Compute platforms with sandboxes
General serverless or app platforms that also offer sandboxes, often with GPUs.
Fly Machines
Fly.io's low-level API for Firecracker VMs that start and stop in under a second and can be suspended to disk; the primitive underneath Fly.io's Sprites product.
- Firecracker microVM
- Pause/resume
How it differs: Teams that want raw, per-second-billed Firecracker VMs they orchestrate themselves rather than a sandbox SDK. A fast, well-priced Firecracker VM primitive for teams that want to assemble their own sandbox layer; for an agent-ready product on the same infrastructure look at Fly.io Sprites.
Modal Sandboxes
Sandboxes on Modal’s serverless compute platform for running untrusted code at very high scale, with GPUs, snapshots and tunnels.
- gVisor or VM
- GPU
- Pause/resume
How it differs: High-concurrency and GPU-backed sandboxes — RL rollouts, evals and coding agents at scale. The best fit when scale or GPUs matter most, especially for teams already on Modal.
Cloud provider code execution
Managed code-execution tools from AWS, Azure, Google Cloud and OpenAI.
AWS Lambda MicroVMs
A Lambda resource type that runs a full Amazon Linux 2023 environment in a Firecracker microVM, restored from a pre-built snapshot, with suspend/resume and an HTTPS endpoint per VM.
- Firecracker microVM
- Pause/resume
How it differs: AWS-native agent sandboxes and interactive sessions that need VM isolation, an inbound endpoint and cheap idle time via suspend. The AWS-native way to get Firecracker-isolated, suspendable sandboxes with a per-VM endpoint, within an 8-hour lifetime and without a higher-level sandbox SDK.
Unikraft Cloud vs alternatives
| Sandbox | Isolation | Open source | Self-host / BYOC | Cold start (vendor) | Max session | Snapshots / pause | GPU | SDKs |
|---|---|---|---|---|---|---|---|---|
| Unikraft Cloud | microVM (modified Firecracker) | No | Yes / Yes | <10 ms (claimed) | Not documented | Yes / Yes | Yes | JavaScript/TypeScript, Python, Go, CLI, REST API |
| AWS Lambda MicroVMs | Firecracker microVM | No | No / No | sub-second to seconds (claimed) | 8 h | Yes / Yes | No | Python, JavaScript/TypeScript, PHP, CLI, REST API |
| Blaxel | MicroVM | No | No / Yes | <25 ms resume | Unlimited (standby) | Yes / Yes | Not documented | TypeScript, Python, Go |
| E2B | Firecracker microVM | Yes | Yes / Yes | Not documented | 1 h / 24 h (Pro) | Yes / Yes | No | Python, JavaScript/TypeScript |
| Fly Machines | Firecracker microVM | No | No / No | <1 s start (claimed) | Not documented | Yes / Yes | Not documented | Go, CLI, REST API |
| Modal Sandboxes | gVisor or VM | No | No / Not documented | <1 s | Up to 24 h | Yes / Yes | Yes | Python, JavaScript/TypeScript, Go |
| Morph Cloud | VM | No | No / Not documented | <250 ms (restore) | Configurable | Yes / Yes | Not documented | Python, TypeScript |
Frequently asked questions
What are the main alternatives to Unikraft Cloud?
Is there an open-source alternative to Unikraft Cloud?
Cite this page
Agent Sandboxes. (2026). Unikraft Cloud alternatives. agentsandboxes.org. Last reviewed November 9, 2026. https://agentsandboxes.org/alternatives/unikraft-cloud/
Found an error or a missing sandbox? Submit a correction — every entry links to the sources it relies on.