smolvm: a lightweight, hardware-isolated VM for running untrusted Python and JS
smolvm boots a real hardware-isolated Linux VM per workload in under 200ms, with network off by default, allow-listed egress, and CPU/RAM caps that stop "while true" loops. Simon Willison's test pass confirms it's a credible option for executing untrusted user code like data transformations. Open source, 4.6k stars.