VPN browser extension vs VPN app: what an extension cannot do

The two things are marketed with the same word and do different jobs. An extension cannot open a tunnel, because no browser gives an extension that power. What it can do is tell the browser to send requests through a proxy, and everything that follows from that distinction is the whole story.

What an extension actually controls

Chrome exposes chrome.proxy; Firefox exposes browser.proxy. Both let an extension set the proxy configuration for that browser. Requests the browser makes go to the proxy, which fetches them and sends the response back, over HTTPS or SOCKS5.

So the extension covers:

• Pages you open in that browser.
• Requests those pages make.
• Nothing else.

What it does not cover

	Extension	App
That browser's traffic	Yes	Yes
A second browser	No	Yes
Desktop apps, mail clients, games	No	Yes
System updates, background services	No	Yes
Torrent clients	No	Yes
Traffic while the browser is closed	No	Yes
Protocol	HTTPS or SOCKS5 proxy	WireGuard, OpenVPN or similar
Needs a driver or system permission	No	Yes

The row that catches people is the second browser. An extension in Chrome does nothing for Firefox, nothing for Edge, and nothing for the embedded browser inside a desktop app that opens a login page.

The one thing extensions do better

Extensions can block WebRTC. That matters because WebRTC is a browser API that asks a STUN server what public address the machine is coming from, and any script on a page can read the answer without a permission prompt. A system VPN changes where traffic exits; it does not change what the browser reports about its own network interfaces, so a full VPN can be running and WebRTC can still describe a real one.

An extension sitting inside the browser can turn that API off or restrict it. That is a genuine capability an app does not have, and it is why running both is a reasonable arrangement rather than a redundant one.

Test yours with the WebRTC leak test.

DNS, handled differently by each

With a system VPN, name resolution goes to whichever resolver the tunnel configures, for the whole machine.

With a SOCKS5 proxy, it depends on a setting. SOCKS5 can resolve names at the proxy or at the client, and a browser configured to resolve locally sends every lookup to your normal resolver while the traffic itself goes through the proxy. Your network operator then holds a list of every domain you opened, which is most of what you were trying to avoid. Chrome's proxyDNS flag and Firefox's network.proxy.socks_remote_dns control this, and any extension worth using sets remote resolution.

Performance

An extension is lighter. There is no virtual adapter, no driver, no system permission, and traffic from everything else on the machine takes its normal path, so a large download in another program does not share the tunnel.

That lightness is exactly the same fact as the coverage gap, viewed from the other side.

When each one is the right answer

Use an extension when you want one browser's traffic to appear from another country, you are on a locked-down machine where you cannot install software, or you want per-tab control with a full VPN doing the real work underneath.

Use an app when you want the device protected. On an untrusted network, on a phone, or anywhere the concern is what the network can see rather than what a website can see, the extension is not sufficient and no configuration of it will be.

VPNmine ships both, and the Chrome and Firefox extensions proxy through the same server network the apps tunnel to. They are not a lighter version of the app; they are a different tool that happens to reach the same servers.

The honest summary

An extension is a proxy with a nice interface. That is not a criticism — a proxy is genuinely useful, and the WebRTC control is something the app cannot offer. It is a criticism of the marketing that calls it a VPN, because someone who installs one believing their device is protected has bought something that protects a browser window.