Skip to content
Codexa

Runtime and previews

The runner service with namespace and cgroup isolation, Docker and E2B drivers, allow-listed commands, a host-based preview proxy and streamed logs.

By Codexa Team1 min read
On this page

Runner service

  • A separate service (not the Next.js process) that materialises project files and runs commands.
  • Default driver: unprivileged user, Linux user/PID/mount/network namespaces, cgroup memory and process limits, per-command timeouts.
  • Optional Docker and E2B drivers selected by operator configuration.
  • Allow-listed commands only: install, build, test, typecheck and the template's dev command.

Previews

  • Start/stop a runtime per project; GET /runtime reports the session and whether the runner is reachable.
  • Host-based proxy mapping one hostname to one sandbox.
  • Logs streamed over SSE (stdout, stderr, system) into the Logs panel.
  • File sync from the editor into the running sandbox.
  • Viewport controls for phone, tablet and desktop widths.
  • Runtime minutes metered against the plan.

Documentation: Troubleshooting, Security.