Browser extension limitations

The Proton VPN browser extension for Chrome and Firefox based browsers provides a quick and convenient way to protect your privacy while browsing the internet.

It prevents websites you visit from seeing your real IP address, prevents your ISP from seeing what you do online, is effective at bypassing most forms of censorship, and allows you to watch your favorite shows, movies, and sports events from a wide selection of popular streaming services safely and securely.

Learn how to use the Proton VPN browser extension

However, any browser extension must work within the limitations imposed by the browser itself. This means that under specific circumstances, the browser extension may not cover all the use-cases of the full Proton VPN app.

Known limitations include:

• Some browsers use protocols that bypass our extension and are not proxied through our VPN servers. For example, some browsers include an embedded email client(new window). This uses email protocols such as SMTP and IMAP(new window), which the browser routes directly to user-supplied third-party email servers without going through our browser extension.
• Browsers decide the order in which they load extensions, and we can’t protect data that’s sent before the Proton VPN extension starts. (Note: We’re working on a partial solution to this problem that will block data from being sent as soon as our extension starts to load, even while the extension is still loading.)
• Other browser extensions can also modify your browser’s settings. However, while we can’t prevent this, the Proton VPN browser extension can detect such changes and will show you a warning when this happens.
• Browsers periodically introduce “experimental” new features. During this experimental testing phase, the features may make connections that don’t respect the browser’s proxy settings (and aren’t routed through to our servers). In most cases, the browser developers detect and fix such issues promptly.
• The Proton VPN browser extension uses HTTPS(new window) to secure your browser’s internet connections. Unlike the full VPN app, which routes all your device’s connections through the same VPN tunnel, each instance of the browser extension creates a new HTTPS connection. This makes your browsing sessions slightly more vulnerable to fingerprinting(new window) attacks than using the full VPN app.

None of these limitations should be a major concern for most people, but you should use our full VPN app if security is a high priority for you.