How agentkernel Compares
Most sandboxes are cloud-hosted services -- you send code to someone else's infrastructure and pay per execution. agentkernel runs on your machine. Your code never leaves your network. No API keys, no vendor accounts, no per-execution billing. Just a single binary that gives each sandbox its own virtual machine.
At a glance
| agentkernel | E2B | Daytona | Docker | Gondolin | Cloudflare | Vercel | Modal | Deno | |
|---|---|---|---|---|---|---|---|---|---|
| Runs locally | yes | -- | -- | yes | yes | -- | -- | -- | -- |
| VM isolation | yes | yes | yes | yes | yes | -- | yes | -- | yes |
| Open source | yes | partial | yes | -- | yes | -- | -- | -- | -- |
| Free / self-hosted | yes | -- | -- | yes | yes | -- | -- | -- | -- |
| CLI tool | yes | -- | -- | yes | yes | -- | yes | -- | -- |
| HTTP API | yes | yes | yes | -- | -- | yes | yes | yes | yes |
| MCP server | yes | -- | -- | -- | -- | -- | -- | -- | -- |
| Secret proxy injection | yes | -- | -- | -- | yes | -- | -- | -- | -- |
| Multi-backend | yes | -- | -- | -- | -- | -- | -- | -- | -- |
| Network policy controls | yes | yes | -- | -- | yes | -- | -- | -- | yes |
| Security profiles | yes | -- | -- | -- | -- | -- | -- | -- | -- |
Details
| agentkernel | E2B | Daytona | Docker | Gondolin | Cloudflare | Vercel | Modal | Deno | |
|---|---|---|---|---|---|---|---|---|---|
| Isolation | Firecracker microVM | Firecracker microVM | VM | microVM | QEMU microVM | Container | VM | Container | Firecracker microVM |
| Boot time | <1µs warm, ~220ms cold | <200ms | <90ms | -- | -- | -- | -- | -- | <200ms |
| Pricing | Free | Pay-per-use | Pay-per-use | Free | Free | Pay-per-use | Pay-per-use | Pay-per-use | Pay-per-use |
| Backends | Firecracker, Docker, Podman, Apple Containers, Hyperlight | Firecracker | Proprietary | Docker | QEMU (KVM/HVF/TCG) | Proprietary | Proprietary | Proprietary | Firecracker |
| SDKs | Python, Rust, Node.js, Go, Swift | Python, JS, Go, Rust | Python, TS, Go | CLI only | TypeScript | TypeScript | TypeScript | Python | TypeScript |
| Agents | Claude, Codex, Gemini, OpenCode | Any | Any | Claude, Codex, Gemini | Any | Any | Any | Any | Any |
| Secrets | Proxy injection, placeholder tokens, file injection | Env vars | Env vars | Env vars | Placeholder injection, per-host allowlists | -- | -- | -- | -- |
| Language | Rust | -- | -- | Go | TypeScript + Zig | -- | -- | -- | -- |
E2B
e2b.dev is the most established cloud sandbox for AI agents. Firecracker microVMs, sub-200ms boot, strong SDK support across Python, JavaScript, Go, and Rust.
Use E2B when: You want a managed cloud service and are building a SaaS product that needs sandboxed execution at scale.
Use agentkernel when: You want local execution, no per-execution costs, and multiple backend options (Firecracker, Docker, Apple Containers).
Gondolin
gondolin is the closest architectural competitor. QEMU-based microVMs with a TypeScript host control plane and Zig guest agent. Strong security model: placeholder secret injection (secrets never enter VM), per-request network policy hooks via JavaScript, TLS MITM for HTTPS inspection.
Use Gondolin when: You want fine-grained per-request network policies with JavaScript hooks. You're in a TypeScript-first ecosystem.
Use agentkernel when: You want faster boot times (Firecracker vs QEMU), smaller images (~25MB vs ~200MB), a smaller attack surface (~50K LOC vs ~1M+ LOC), and multiple backend options including Docker fallback on macOS. agentkernel also offers proxy injection, placeholder tokens, and file-based secret injection.
Daytona
daytona.io provides cloud sandbox infrastructure with sub-90ms boot times, Git integration, and LSP support. SDKs in Python, TypeScript, and Go.
Use Daytona when: You want cloud-hosted sandboxes with Git integration and IDE features.
Use agentkernel when: You want local execution, hardware-level VM isolation, and built-in agent compatibility modes.
Docker Sandboxes
Docker AI Sandboxes run lightweight microVMs with private Docker daemons. Supports Claude Code, Codex, Gemini, and Docker's own agent (cagent).
Use Docker when: You already use Docker Desktop and want sandboxing integrated into that workflow.
Use agentkernel when: You want an independent tool with Firecracker microVMs, an HTTP API, MCP server, and alternative backends (Podman, Apple Containers, Hyperlight).
Cloudflare Sandbox
Cloudflare Sandbox provides container-based sandboxes with a TypeScript SDK, preview URLs, and WebSocket support.
Use Cloudflare when: You're building on Cloudflare Workers and want sandboxes close to your edge infrastructure.
Use agentkernel when: You want local execution and VM-level isolation instead of container isolation.
Vercel Sandbox
Vercel Sandbox provides ephemeral Linux VMs with a TypeScript SDK. Node.js and Python runtimes.
Use Vercel when: You're building on Vercel and want integrated observability dashboards.
Use agentkernel when: You want local execution with 12+ auto-detected language runtimes.
Modal Sandboxes
Modal Sandboxes provide container-based environments with a Python SDK. Strong in the ML community with up to 24-hour sessions.
Use Modal when: You're already using Modal for ML workloads.
Use agentkernel when: You want local execution, VM-level isolation, and a CLI tool (not Python-only).
Deno Sandboxes
Deno Sandboxes use Firecracker microVMs with a JavaScript API. Under 200ms boot and network policy controls.
Use Deno when: You're in the Deno ecosystem and want managed Firecracker.
Use agentkernel when: You want local execution, multi-language auto-detection, and multiple backend options.
Other notable projects
stereOS -- Purpose-built NixOS-based operating system for AI agents. Produces bootable VM images ("Mixtapes") with stereosd (system daemon) + agentd (agent lifecycle via tmux). Complementary to agentkernel — builds the guest OS, not the host runtime.
Browser Use -- Production agent infrastructure (79K stars) using Unikraft micro-VMs. Pioneered "Pattern 2" — isolate the entire agent, not just tools. Agent gets zero secrets, talks to a control plane that proxies all external calls.
justbash.dev -- Pure TypeScript bash interpreter with in-memory virtual filesystem. ~0ms cold start but no real isolation, no binary execution. Vercel Sandbox API-compatible upgrade path confirms the lightweight→VM isolation spectrum.
OpenAI Symphony -- Issue-to-PR orchestration in Elixir. Polls Linear, spawns agents, manages multi-turn lifecycle. Its spec explicitly calls for "external isolation layers" — the infrastructure agentkernel provides.
Fly.io Machines -- Firecracker-based VMs with millisecond boot times. General-purpose compute, usable as a sandbox backend.
Rivet Sandbox Agent SDK -- Universal API normalizing interactions across multiple sandbox providers (Daytona, E2B, Vercel, Docker). An abstraction layer rather than infrastructure.
agentkernel's position
agentkernel occupies a specific niche: local-first, VM-isolated sandboxing for AI coding agents.
Most alternatives are cloud services — the right choice for SaaS products at scale. But they require sending code to a third party, charge per execution, and add a network dependency.
agentkernel is for developers who want to run AI agents on their own machines with real isolation. On Linux, you get Firecracker microVMs — the same technology behind E2B, Deno Sandboxes, and AWS Lambda. On macOS 26+, Apple Containers provide native VM isolation. On older macOS, Docker and Podman are fallbacks.
The trade-off: you run the infrastructure yourself. For a single developer or small team, that's a feature. For a platform serving thousands of users, a managed cloud service is the better fit.