SandCastle
Developer Tool
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