CodeSandbox vs Sandlock

CodeSandbox is a web and iOS service for creating isolated development environments that execute code. Its SDK can spin up environments programmatically, while microVMs can be started, cloned, or restored from snapshots within two seconds. Snapshots let work resume in the same sandbox after inactivity, and users can set the inactivity period before automatic hibernation. Multiple agents can run in parallel without interfering, and forking supports A/B testing of different agents. Tests can run inside sandboxes for CI/CD, with environments able to hibernate after completion. Sandpack provides live browser coding, Storybook Integration creates a playground for each story, and CodeSandbox lists a VS Code extension. The service says it can handle millions of concurrent VMs. CodeSandbox was founded in 2017, is headquartered in Amsterdam, and CodeSandbox BV is a Together AI company.

Sandlock is a Linux process sandbox for confining untrusted code with policies enforced by the kernel. It uses Landlock, seccomp-bpf, and seccomp user notification to control filesystem access, network activity, system calls, and resource use. Policies can deny network egress by default, apply HTTP method, host, and path rules, stage writes through copy-on-write, and set resource limits. A supervisor can attach credentials through a proxy after an HTTP access check, keeping the secret value out of the sandboxed workload. Interfaces include a CLI, Python SDK, Rust API, Go SDK, OCI runtime, and MCP server. The OCI runtime works with containerd, CRI-O, and Kubernetes, while the remote MCP API can connect to Claude Desktop, Cursor, or another MCP client. Sandlock runs as an ordinary user without root, a container runtime, or a hypervisor. Linux 6.12 or later supports the full protection set by default; older kernels require explicit waivers for missing protections. It shares the host kernel, excluding kernel vulnerabilities and hardware side channels from its guarantees.