is-port-open

A simple and lightweight Node.js package to check if a port is open on a given host using async socket connections.

Installation

npm install is-port-open

Usage

const isPortOpen = require('is-port-open');

// Check if port 80 is open on localhost
isPortOpen(80)
  .then(isOpen => {
    console.log(`Port 80 is ${isOpen ? 'open' : 'closed'}`);
  });

// Check if port 443 is open on a specific host
isPortOpen(443, 'google.com')
  .then(isOpen => {
    console.log(`Port 443 is ${isOpen ? 'open' : 'closed'}`);
  });

// With custom timeout (in milliseconds)
isPortOpen(8080, 'localhost', 5000)
  .then(isOpen => {
    console.log(`Port 8080 is ${isOpen ? 'open' : 'closed'}`);
  });

// Using async/await
async function checkPort() {
  const isOpen = await isPortOpen(3000);
  console.log(`Port 3000 is ${isOpen ? 'open' : 'closed'}`);
}

API

isPortOpen(port, host?, timeout?)

Returns a Promise that resolves to true if the port is open, false otherwise.

Parameters

• port (number, required): Port number to check (1-65535)
• host (string, optional): Host to check. Default: 'localhost'
• timeout (number, optional): Timeout in milliseconds. Default: 2000

Returns

• Promise<boolean>: true if port is open, false if closed or unreachable

Throws

• Error: If port number is invalid (not between 1 and 65535)

Use Cases

Perfect for CLI tools and scripts that need to:

• Check if a service is running before starting
• Verify port availability before binding
• Monitor service health
• Test network connectivity

License

MIT

Author

malvabombom

Repository

https://github.com/holasoymalva/is-port-open