A sandbox is a KVM microVM started from a template. It has its own Linux kernel, a writable root filesystem, and its own network policy. Inside it, E2B’s envd daemon serves commands, files and terminals on port 49983; the SDKs and the CLI talk to it through the Anona gateway.

Metadata and listing

Attach string metadata at create time, then filter on it when you list:
Metadata keys starting with anona. are reserved and refused.

Connect from anywhere

A sandbox outlives the process that created it. Any process holding an API key of the same organization can reconnect by ID:
Another organization’s sandbox answers “not found”, exactly like a sandbox that does not exist.