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SandCastle

Developer Tool • March 15, 2026

The fastest way to run untrusted JavaScript safely. Zero config, auto-detects Bun/Node.js, 380K ops/sec.

TypeScript
C++
Bun
Node.js
V8
Security
NPM Package
Open Source

Key Features

  • •Zero config — install and run, no binaries or Docker needed
  • •Auto-detects runtime and picks fastest isolation backend
  • •380K ops/sec on Node.js via isolated-vm, 66K ops/sec on Bun
  • •Console capture, input injection, timeouts, and error handling built in
  • •Memory-limited sandboxes with configurable constraints
  • •One-line API for evaluating untrusted code safely