Kernel alternatives
The 6 alternatives below are grouped by kind of sandbox, and each says what it does differently from Kernel. Start from whatever made you look: missing GPUs, session limits, self-hosting, pricing or isolation.
Why teams look beyond Kernel
Hypervisor-isolated browsers with standby billing and open images, the most transparent isolation story among the closed clouds.
- Hypervisor is not named and the self-hosted unikernel path targets Unikraft Cloud rather than a local setup
- Region selection, GPU and BYO proxies require the $200/month Start-Up plan
- The documented cold-start figures vary between pages (under 20 ms, ~30 ms p50, 794 ms benchmark)
- ISO 27001 and GDPR are still in progress
Kernel alternatives, by kind
Compute platforms with sandboxes
General serverless or app platforms that also offer sandboxes, often with GPUs.
Unikraft Cloud
Millisecond-start microVMs built from Dockerfiles on a modified Firecracker VMM, with stateful scale-to-zero, live forking ("branching") and checkpoints, plus a Sandbox SDK for agents.
- microVM (modified Firecracker)
- Self-hostable
- BYOC
- GPU
- Pause/resume
How it differs: Agent fleets that need thousands of sandboxes per server, millisecond stateful wake-ups and live forking of running environments. A density- and latency-focused microVM platform whose stateful forking and shielded egress suit large agent fleets, if you can work with unpublished pricing.
Browser and desktop sandboxes
Hosted browsers and full desktops that computer-use agents click, type and browse in.
Anchor Browser
Cloud browsers for agents with a dedicated VM per browser, managed authentication identities, persistent volumes and a Web-Bot-Auth-verified Chromium fork.
- Dedicated VM per browser
- BYOC
How it differs: Authenticated enterprise workflows that need VM-level isolation per browser and managed logins. The strongest isolation story in this group, a dedicated VM per browser, paired with managed authentication for enterprise agents.
Browser Use Cloud
Stealth cloud Chromium at $0.02 per browser hour from the makers of the MIT-licensed Browser Use agent library, with profiles, live view, an EU deployment and a hosted agent API.
- Isolated browser per run
How it differs: Cheap stealth browser hours for agents built on the Browser Use library or any CDP client. Inexpensive stealth browsers with audited compliance and an EU option, best suited to teams already on the Browser Use library.
Browserbase
Hosted headless Chromium sessions for web agents, driven over CDP with Playwright, Puppeteer, Selenium or the Stagehand SDK, with Contexts for persisted logins and four regions.
- Isolated Chromium session
How it differs: Web agents that need managed Chromium at scale with persisted logins and stealth. A mature managed-Chromium service for web agents, with strong SDK and framework coverage but an undocumented isolation boundary.
Hyperbrowser
Credit-billed cloud Chrome sessions with profiles, stealth and captcha solving, plus one-shot agent runs (Claude Computer Use, OpenAI CUA, Browser Use) and separate VM-based code sandboxes.
- Isolated browser instance
How it differs: Agents that need cheap browser hours with a built-in path to run computer-use models as one-shot tasks. A credit-priced browser cloud with the broadest built-in agent-model support, held back by thin isolation and compliance documentation.
Steel
Open-source browser API for agents (Apache-2.0, self-hostable with Docker) with a managed Steel Cloud adding stealth, captcha solving, profiles and a hosted MCP server.
- Isolated Chromium session
- Open source
- Self-hostable
How it differs: Teams that want an open-source browser API they can run themselves or scale on a managed cloud. The open-source choice among hosted browser APIs: self-host for free, move to Steel Cloud for stealth, captchas and concurrency.
Kernel vs alternatives
| Sandbox | Isolation | Open source | Self-host / BYOC | Cold start (vendor) | Max session | Snapshots / pause | GPU | SDKs |
|---|---|---|---|---|---|---|---|---|
| Kernel | Unikernel VM per browser | Yes | Yes / No | ~30 ms p50 (claim) | Up to 72 h | Yes / Yes | Yes | JavaScript/TypeScript, Python, Go, CLI, REST API, MCP server |
| Anchor Browser | Dedicated VM per browser | No | No / Yes | Not documented | 3 h default, configurable | No / No | No | Python, JavaScript/TypeScript, REST API, MCP server |
| Browser Use Cloud | Isolated browser per run | No | No / No | Not documented | 1 h default, 4 h max | No / No | No | Python, JavaScript/TypeScript, REST API |
| Browserbase | Isolated Chromium session | No | No / No | <2 s (claim) | 6 h (15 min Free) | No / No | No | Python, JavaScript/TypeScript, REST API, MCP server |
| Hyperbrowser | Isolated browser instance | No | No / No | <500 ms (claim) | Up to 12 h | No / No | No | Python, JavaScript/TypeScript, CLI, REST API, MCP server |
| Steel | Isolated Chromium session | Yes | Yes / No | Not documented | 15 min / 1 h / 24 h | No / No | No | Python, JavaScript/TypeScript, Go, Rust, CLI, REST API, MCP server |
| Unikraft Cloud | microVM (modified Firecracker) | No | Yes / Yes | <10 ms (claimed) | Not documented | Yes / Yes | Yes | JavaScript/TypeScript, Python, Go, CLI, REST API |
Frequently asked questions
What are the main alternatives to Kernel?
Is there an open-source alternative to Kernel?
Cite this page
Agent Sandboxes. (2026). Kernel alternatives. agentsandboxes.org. Last reviewed November 9, 2026. https://agentsandboxes.org/alternatives/kernel/
Found an error or a missing sandbox? Submit a correction — every entry links to the sources it relies on.