How do I register a custom URL protocol in Windows?

The MSDN link is nice, but the security information there isn't complete. The handler registration should contain "%1", not %1. This is a security measure, because some URL sources incorrectly decode %20 before invoking your custom protocol handler.

PS. You'll get the entire URL, not just the URL parameters. But the URL might be subject to some mistreatment, besides the already mentioned %20->space conversion. It helps to be conservative in your URL syntax design. Don't throw in random // or you'll get into the mess that file:// is.

There is an npm module for this purpose.

link :https://www.npmjs.com/package/protocol-registry

So to do this in nodejs you just need to run the code below:

First Install it

npm i protocol-registry

Then use the code below to register you entry file.

const path = require('path');

const ProtocolRegistry = require('protocol-registry');

console.log('Registering...');
// Registers the Protocol
ProtocolRegistry.register({
    protocol: 'testproto', // sets protocol for your command , testproto://**
    command: `node ${path.join(__dirname, './index.js')} $_URL_`, // $_URL_ will the replaces by the url used to initiate it
    override: true, // Use this with caution as it will destroy all previous Registrations on this protocol
    terminal: true, // Use this to run your command inside a terminal
    script: false
}).then(async () => {
    console.log('Successfully registered');
});

Then suppose someone opens testproto://test then a new terminal will be launched executing :

node yourapp/index.js testproto://test

It also supports all other operating system.

If anyone wants a .reg file for creating the association, see below:

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\duck]
"URL Protocol"=""
[HKEY_CLASSES_ROOT\duck\shell]
[HKEY_CLASSES_ROOT\duck\shell\open]
[HKEY_CLASSES_ROOT\duck\shell\open\command] 
@="\"C:\\Users\\duck\\source\\repos\\ConsoleApp1\\ConsoleApp1\\bin\\Debug\\net6.0\\ConsoleApp1.exe\" \"%1\""

Pasted that into notepad, the file -> save as -> duck.reg, and then run it. After running it, when you type duck://arg-here into chrome, ConsoleApp1.exe will run with "arg-here" as an argument. Double slashes are required for the path to the exe and double quotes must be escaped.

Tested and working on Windows 11 with Edge (the chrome version) and Chrome