pid-port

Get the ID of the process that uses a certain port

Install

npm install pid-port

Usage

import {portToPid} from 'pid-port';

try {
    // Only checks localhost by default
    console.log(await portToPid(8080));
    //=> 1337

    // Same as above
    console.log(await portToPid({port: 8080}));
    //=> 1337

    const pids = await portToPid([8080, 22]);

    console.log(pids.get(8080));
    //=> 1337

    console.log(pids.get(22));
    //=> 12345

    // Specific host
    console.log(await portToPid({port: 8080, host: '127.0.0.1'}));
    //=> 1337

    // Check all interfaces (use with caution)
    console.log(await portToPid({port: 8080, host: '*'}));
    //=> 1337
} catch (error) {
    console.log(error);
    //=> 'Could not find a process that uses port `8080` on localhost'
}

API

portToPid(portOrOptions)

Get the process ID for a port.

Returns a Promise<number | undefined> (integer) with the process ID.

[!NOTE] By default, only checks localhost (127.0.0.1 and ::1). Use {host: '*'} to check all interfaces if needed.

Linux privilege requirements: On Linux systems, process ID information may not be visible to non-privileged users. If a port is found but no PID is returned, the package will attempt to use lsof as a fallback (requires lsof to be installed).

portOrOptions

Type: number | {port: number, host?: string}

Either a port number directly, or an options object with:

• port (number): The port to look up
• host (string, optional): The host to filter by. Use '*', '0.0.0.0', or '::' for all interfaces. Use 'localhost' for explicit localhost filtering.

portToPid(ports)

Get the process IDs for multiple ports.

Returns a Promise<Map<number, number>> (integer) with the port as key and the process ID as value.

@example

import {portToPid} from 'pid-port';

try {
    const pids = await portToPid([8080, 22]);

    console.log(pids.get(8080));
    //=> 1337

    console.log(pids.get(22));
    //=> 12345
} catch (error) {
    console.log(error);
    //=> 'Could not find a process that uses port `8080`'
}

ports

Type: number[] (integer)

The ports to look up.

pidToPorts(pid)

Get the ports for a process ID.

Returns a Promise<Set<number>> with the ports.

@example

import {pidToPorts} from 'pid-port';

try {
    const ports = await pidToPorts(1337);
    //=> Set { 8080, 22 }
} catch (error) {
    console.log(error);
}

pid

Type: number

The process ID to look up.

pidToPorts(pids)

Get the ports for multiple process IDs.

Returns a Promise<Map<number, Set<number>>> with the process ID as the key and the ports as value.

@example

import {pidToPorts} from 'pid-port';

try {
    const ports = await pidToPorts([1337, 12345]);
    //=> Map { 1337 => Set { 8080, 22 }, 12345 => Set { 3000 } }
} catch (error) {
    console.log(error);
}

pids

Type: number[]

The process IDs to look up.

allPortsWithPid(options?)

Get all ports with their process ID, optionally filtered by host.

Returns a Promise<Map<number, number>> (integer) with the port as key and the process ID as value.

[!NOTE] By default, only checks localhost (127.0.0.1 and ::1). Use {host: '*'} to check all interfaces if needed.

@example

import {allPortsWithPid} from 'pid-port';

try {
    // Only localhost ports
    const localhost = await allPortsWithPid();
    //=> Map { 8080 => 1337, 22 => 12345 }

    // Specific host
    const filtered = await allPortsWithPid({host: '127.0.0.1'});
    //=> Map { 8080 => 1337, 22 => 12345 }

    // All interfaces (use with caution)
    const all = await allPortsWithPid({host: '*'});
    //=> Map { 8080 => 1337, 22 => 12345, 3000 => 14311 }
} catch (error) {
    console.log(error);
}

options

Type: object (optional)

host

Type: string (optional)

The host to filter by. Use '*', '0.0.0.0', or '::' for all interfaces.

portBindings(port, options?)

Get all process bindings for a specific port.

Returns a Promise<Array<{host: string; pid: number}>> with detailed binding information.

[!NOTE] By default, only checks localhost (127.0.0.1 and ::1). Use {host: '*'} to check all interfaces if needed.

@example

import {portBindings} from 'pid-port';

try {
    // Only localhost bindings
    const bindings = await portBindings(8080);
    //=> [{host: '127.0.0.1', pid: 1337}]

    // All interfaces (use with caution)
    const allBindings = await portBindings(8080, {host: '*'});
    //=> [
    //   {host: '127.0.0.1', pid: 1337},
    //   {host: '192.168.1.1', pid: 5678}
    // ]
} catch (error) {
    console.log(error);
}

port

Type: number (integer)

The port to look up.

options

Type: object (optional)

host

Type: string (optional)

The host to filter by. Use '*', '0.0.0.0', or '::' for all interfaces.

Related

• fkill-cli - Uses this package to let you kill the process that occupies a certain port
• pid-cwd - Find the working directory of a process from its process ID