Firefox tests HTTPS-First Mode in Nightly

Three years after making HTTPS the default in Private Browsing mode, Mozilla is testing an upgrade to prioritize HTTPS connections in regular browsing windows. This feature, known as HTTPS-First Mode, is currently available in Firefox Nightly, version 129.

HTTPS-First Mode in Mozilla Firefox improves web browsing security by prioritizing HTTPS connections. It encrypts communication between your browser and websites, safeguarding sensitive data (such as login credentials and financial information) from interception by hackers on insecure networks. Moreover, HTTPS ensures data integrity, preserving the accuracy of information exchanged.

When you try to visit a website, Firefox will first attempt to upgrade the connection to HTTPS, even if the website doesn’t explicitly use it.

If the upgrade fails, Firefox will display a warning informing you that the connection is insecure. This helps you make informed decisions about whether to proceed to the website.

HTTPS-First Mode in Firefox Nightly

Mozilla initially enabled HTTPS by default in Private Browsing mode with Firefox 91. They are now testing HTTPS-First Mode by default in the Nightly version (version 129), scheduled for release on August 6, 2024

This change improves security for users browsing in the Firefox Nightly version. Once Mozilla evaluates user feedback, they may eventually make it the default setting in the stable version as well, although the exact timeframe is unknown.

While HTTPS-First Mode might lead to minor compatibility issues with some older websites or a slight performance impact in rare cases, the security benefits far outweigh these potential drawbacks.

“Starting with Firefox 129, Firefox Nightly will automatically try to use a secure HTTPS connection whenever possible in loading a page. This behavior is known as “HTTPS-First”, or “HTTPS Upgrades”, and has been the default in Firefox’s private browsing mode since Firefox 91. Here is a blog post from when this feature was introduced in Private browsing.” Mozilla notes in Nightly release notes.

It is worth noting, that Google is still testing HTTPS First Mode for Chrome in Incognito Mode.

Following Mozilla’s confirmation of upcoming features like vertical tabs, tab groups, and AI functionalities, we previously reported on how to enable vertical tabs in Firefox.