Week of May 1, 2026

New features

Redesigned TypeScript SDK

Builder API matching the Rust SDK, with await using, typed errors, async iterables, and bundled native binaries (no postinstall download).

await using sandbox = await Sandbox.builder("my-sandbox")
  .image("alpine:latest")
  .cpus(2)
  .create();

See the TypeScript SDK reference.

Redesigned network policy

--network-policy is gone. Rules now carry their own direction, action, target, protocol, and ports through a single grammar: <action>[:<direction>]@<target>[:<proto>[:<ports>]].

msb run alpine --name agent \
  --net-default-egress deny \
  --net-rule "allow@public,allow@host" \
  --net-rule "deny@private:tcp:445"

See the networking overview.

Other features

• Disk-image volume mounts. Attach qcow2, raw, or vmdk images as virtio-blk devices at any guest path; readonly is now consistent across volume types. See Sandbox volumes.
• Inline --script flag. Register scripts on the command line with --script NAME=BODY; the file form is now --script-path NAME:PATH. See the CLI reference.
• msb alias. Installs from npm, pip, and cargo now put both microsandbox and msb on PATH.
• host.microsandbox.internal. Sandboxes can reach the host through this well-known DNS name.
• Trust host CAs (opt-in). Sandboxes can trust the host's CA bundle for internal TLS endpoints. See Networking TLS.
• DNS interception over TCP/53 and DoT/853. Closes gaps where apps bypassed policy by switching transports. See Networking DNS.
• Custom TLS certs and insecure registries for self-hosted image registries. See the images overview.
• Per-sandbox libkrunfw override for SDK callers developing against unreleased firmware.
• Installer rejects unsupported glibc up front, instead of producing confusing runtime errors.

Bug fixes

• Domain and suffix= rules now enforce consistently across DNS, SNI, and policy layers.
• The Node/TypeScript SDK supports the same secret injection options as the Rust SDK.
• macOS reads system nameservers via SCDynamicStore, matching what the OS actually uses.
• The npm platform package ships libkrunfw under its canonical name, fixing load failures on some Linux distros.